Heres something I learned by mistake by looking over a DDickson Marabou Leech.
I made a beginners mistake of tearing off barbs and clumping them on the hook and spinning them, what a hassle. I now just dampen my fingers in water and comb back the barbs on the spine just like rooster hackle and then just use the standard palmer by hand not the rotator of a Renzi. It may look ugly at first but when its totally dried..its looks awesome and clean! I'm glad I finally realized this technique.
Also for the front hook that you cut, use a cheaper hook and not your Tiemcos or Katsus which you use for the rear hook.
These are AWESOME flies to tie and I can email you some pics of my flies if you would like and maybe give you some Basic techniques I use. Good luck!
"Follow Me and I will make you fishers of Men" Matthew 4:19
Tying an articulated or string leech is not much different that tying a bunny leech. Just cut the top rabbit strip longer so it extends back over the trailer hook and tie it in just in front of the bend. Besides using cross-cut rabbit on the lead hook, you can also try using a maribou collar hackle.
The real challenge though is in attaching the trailer hook to the lead hook shank. Use mono or dacron looped through the eye on the trailer hook, tied along the shank of the lead hook, then doubled back and tied again with a drop or two of Zap A Gap for good measure. If using mono, use the heaviest size that you can get doubled through the eye of the trailer hook.
Remember that with either mono or dacron, the connection will tend to twist around the shank of the lead hook as you're tying it in so experiment by positioning the connection to compensate for the amount of the twist.
"When you come to the fork in the road, take it." ~ Yogi Berra
I've been reading these posts with interest, as I'm about to attempt some articulated flies for a friend (and of course, for myself, too).
I really like what I think you're describing here (in regards to dampening and combing back the barbs) and will try this as I work on these.
I do have another question. I've seen various suggestions for what to use to join the front and trailer hooks. Piano wire, mono, dacron, kevlar...any recommendations?
Has anyone tried upholstery thread? It looks pretty stout, seems to compact well and is fairly easy to work with, just uncertain about the "breaking point" or any other unforeseen deficiencies.
Anyone used this thread for anything comparable? Would or would not recommend?
Fortuna's instructions are good for a string leech, but an articulated leech is slightly different. A string leech is more free too move as it pleases, whereas an articulated fly has a joint between two hook shanks with the fly tied onto both shanks (fly fishing equivalent of a Jointed Rapala). The link that TroutGuy posted shows a typical articulated-style fly.