So here's the report. Fishing was tough this year on the McCloud - really high, off-color water. I got a bit of action every day, and had a couple of good sessions, but I also got in a lot of "casting practice." Except for two evenings, the action was all subsurface, so dry dropper fishing was basically thinly disguised indicator nymphing. My rig was a really big Chubby Chernobyl (that didn't get even one hit) suspending a beadhead jig stonefly nymph and another smaller beadhead nymph below that. This is a big, complex, draggy rig to cast.
Over all, the line did exactly what I hoped it would. I was able to motivate the terminal tackle mostly to where I wanted it to go. Because the water was so high, access was challenging and I had a lot of brush right behind and above me most of the time. So I was definitely performing different kinds of single-Spey, double-Spey, and Snap-T casts to avoid getting tangled up in the brush. I also set up a soft hackle rig for part of the time and experimented with 5' poly leaders, both intermediate and fast sinking. I fished an evening hatch with this rig and picked up a nice rainbow on the swing. I did not have a chance to really shoot the line with overhead casts. that will have to wait for a Sierra lake trip later in the summer.
So - for rivers, this rig works pretty, pretty well. I can get out 40+ feet under tough casting conditions (no backcast, lots of brush, etc.) with no problem.
One more note - The Larry Kenny 8055 is AWESOME. Super happy with it. Worked well with this "specialty" line setup and a garden-variety 5 wt line for dry fly fishing in the evening. Going to sell all my other rods. (well, maybe not that last part).