Read the first 3, maybe 4 pages. Beyond that you'll be wading through crap, in large part thanks to me. But the first 3 pages have alot of good info from folks who know what they are talking about AND who have different styles and preferences. There is as close to some "truth" as you will find when that happens.
I've tried a 5wt 40+ on my 4wt z for shit's and giggles, it bombs the line but with the head all the way out it sure loads like a mofo...Knowing salt rods tend to be stiffer I wondered if that was the reasoning behind the over loading? Now I'll start with the 8wt on my 7 and work up if needed!!!
And here I thought it was just the spey rods that were finicky line whores!!!
Well, it's dangerous to generalize, but as even cheap rods get up into the higher modulus graphites, with even just "adequate" rod design, they recover so quickly that overloading the rod really stops being an insurmountable problem. The rods recover so quickly after delivering the load, that you can get away with crazy heavy loads as long as you alter your stroke. So you end up with a rod that the caster can "customize" depending on his casting style, by picking different lines. This has always been the case, but now the range of customization you can explore is so vast because there are so many lines, and the rods will cast such a wide range of loads so well, that it's easy to think the rods are finicky line whores. It's not the rods. It's us... Incremental differences in weight and taper can be felt so well, that if you know what you like in terms of feel, you can really get crazy and try to find THE line.
Also, when you say that's all he'd fish if he had to choose, do you mean the line, the setup, or . . . ? What configuration of 40+? (floating, intermediate, etc.)?
To me, a 7 wt. is on the big side for the all-around Puget Sound stick. If that's what you have, that would work great, but for at least 10 months out of the year a six weight is considered by many to be a perfect all-around line weight, with the other couple of months (say, chum or king time) arguably justifying a higher line weight rod. A few years ago a buddy started a 9'6" Z Axis 7 weight and a 9'6" BIIx 6 weight as his beach equipment; the 7 weight last year was replaced with a second BIIx.
With that said, a few years ago Capt. Keith Robbins (guides out in the Sound), who offers 6, 7, and 8 weight rods to use on his boat, said the 7 weight for him was his favorite all-around stick. He fishes fast sinking lines, using different lines than a beach fisherperson might, and not targeting searuns (typically) as often as a beach fisherperson.