The most effective (for Kings) I've run into is just a black chenille body with a lime or chartreuse hackle. 'Fly De Jur' (sp????) on the lower Chetco for the guys in the boat line. Don't ask me about Coho ...... never have hooked one of the damned things! And not for lack of trying .......
Off the top of my head, why spey rods make lousy coho rods:
13'+ of soft spey rod and a rear grip means fishing a retrieve is awkward.
coho are spooky and hang out in calm water, where noise won't go unnoticed, speycasting rips the line off the surface, makes a lot of noise and will spook coho. Even if you get away with tearing the line off the surface, land a skagit head anywhere near a school of coho and that's the last you'll see of them.
coho dont hang out where you can easily swing for them normally.
coho aren't even usually interested in a swung fly, they want a stripped retrieve
packing a spey rod through the bush to get to a coho spot is begging for trouble
coho follow your fly until the last second often. when you reach the running line- head connection, your fly will still be up to 40' out still. for this reason alone, a spey rod isn't the any good for coho.
If you want to catch coho, find a backwater adjacent to the main flow, even better if it has a creek dumping in, and cast BH olive wooly buggers, "christmas trees", bead head muddler or clousers on a clear tip. You'll catch fish. Coho are the spookiest of all anadromous fish though, so don't splash, land the fly softly etc...
Chinook... I've only caught them on the Dean and most of them completely kicked my ass. They to like deeper water and don't mind if its slower either. They don't really act like steelhead. Blue, black and chartreuse seemed to work well.
Chinook like deep water for sure! DEEP holes like elbow hole on the NF Stilly stack chinook like cordwood. You arent fishing for them if youre not ticking bottom! If theres Chinook in the hole, there ARENT STEELHEAD thats for sure. Kings are bullies. A really heavy fly under a big indicator definitely has its place in holes/slots that are deep and fast.
So I haven't caught many kings on a fly rod lately but back when Alaska had kings I'd guide for them and had great succes swinging with a single hander from a boat. I feel like when you want the fly really deep a single hander is a much better tool than a two hander. We would use T300 lines and swing down and across, typically the strike would come on the hang down (if the clients ever listened to me about letting it sit there they'd get bit). This was fairly big water, a river mouth scenario. I think the same approach would work well on the snake or deschutes or wherever, but you'd have to dial in your line so that its right on the bottom, I would reccomend for this a shooting head system with various heads of T 14, T 17 and T 20 loop to looped. I have done alright using this system in down years, but haven't really wanted to put in the time. I was guiding back before intruders and stuff but my best flies were 5/0 orange bunny flies with a shit ton of flashabou, red 3/0 flash flies, and once in a while something black. I've since modified my designs quite a bit and have really settled on double marabou intruders with a feather wrapped at the rear around a shit ton of flash, a body of something big and a front wrapped marabou then some contrasting shlappen. Orange and chartruse with silver flash is my favorite.
Kings probably hit swung flies the best of all the salmon (closely followed by chums) so a spey rod is a great tool for them, the thing about it is that you (for the most part) gotta be on their level, this means big rods and big lines and dialing in your sink tip systems just right, other spey rodders with big budgets on heads and rods are better than this than me.
In smaller water where is definate pools and you know where the fish are gonna hold either chuck and duck methods with a lot of shot or indicator rigs are great. I prefer indicators just for the asthetics of it. Back in the day I had to use two or three corkies to keep my rig up (now a fatty ass thingambobber will do the trick), and typically I'd throw smaller steelhead style flies like polar shrimp, sparkle shrimp, also everglow flies, and even things like orange woolly buggers. I would tie these in 3 basic colors chartruse, orange, and bright pink. Some days the fish prefer different color options. I also carry some weird contrasting buggers (chart, blue and black) and whatnot just in case. And I'd nymph the hell out of the pools, and do really well, sometimes flies as small as 8 were necessary. Kings, like steelhead aren't really that picky, if they are gonna hit they are gonna hit, if they aren't they aren't move on. THis is my favorite type of king fishing, unfortunately the runs (and my work schedual) have been so piss poor I haven't been able to do it much.
Chuck and duck methods have their place. Closed mouth kings often just have to be pounded into submission and you'll eventually get one, it just takes time.
Sight fishing for kings is probably the best thing ever, they don't usually move to far to get the fly so just put it in front of their face, they'll eat or move on. Although I did have fish last summer come 25 feet to slam a dolly fly I was fishing with my 4 weight.
Obviously my experience in AK will be different then yours but those are the techniques that have worked for me, good luck.
As for hos find them in a slough or backwater and cast an ESL on a floating line, if they don't hit it find new fish.
Lastly, fish saltwater when they are feeding, its a whole different game.
Gotta agree with power monkey , spent the better part of 40 yrs in that country , family , uaf and commercial fishing. Always did good in the salt especially aroun seward early season and also up the beach at tonsina pt ,or acroos the bay at 4th of uly creek . Here I am fishing the icicle generally get down from the drifters or go fish the rock gardens where every one is afraid of losing gear, personal best was an 18 lb hen put on a real and proper show for her species , then to throw a bucket of salt in the mix I released her ,boy were the bankies mad. I realize this is a terminal fishery but she earned it smitty
My experience is pretty limited so take this with a grain of salt. Have only targeted them in AK. Have fished from a boat with single hander, heavy sink tips and big flies. (This is still fishing on the swing, not nymphing; it's just that you anchor in one place where fish are likely holding or moving through and cast multiple times. Pull anchor and drop down a bit, repeat.) Have also fished for them with a spey rod in AK, very similar to cast-and-step fishing on the swing for steelhead (although not exactly the same kind of water). Where I fished for them, big flies (bunny leeches, Bjorns prawns, Intruders, Pick yer pockets, Skagit Minnows) in all sorts of colors worked - pink, chartreuse, purple, blue, black, etc. Not sure I agree with the statement that you have to be ticking bottom, at least in my experience. Have hooked a number of fish in the middle of the water column, but definitely you need to fish a sink tip if you're trying to catch them on the swing. In my experience, these fish generally do not slam the fly - you tend to get soft, long pulls and you have to let them take it for a while before setting the hook or you'll end up with a lot of missed fish. Have also occasionally hooked them in Washington fishing for steelhead. Hooked a big one on the Wenatchee last fall swinging a size 8 Brad's Brat on a floating line and polyleader. That one was definitely a surprise.