Joni, Have you tried a sinking line for the chironamid or Callibaetis thang?
A 300 grain gets down there, you can cast it, and (most evil of all) you can vertically jig it. Fin and twitch for some fun too!
You can rig your flies czech nymph style and still use an indicator, or, fish them on stillwater, while slowly trolling your float tube. I have done both, in the river, unless you lead the heavy fly a little, you lose some contact with the trailing fly, but, using a weighted fly (tungsten, lead sub, etc), 2 feet up the line, with a non-weighted trailing fly does work pretty well, even on the lake (when your moving a little). You can een use an indicator with this rig in faster water fishing just on the fast side of a seam.
If you are fishing a 2 nymph rig, put some weight between the 2 flies, and ahead of the 1st fly.
9 ft. 5x leader - weight - size 14 tungsten beadhead - 2 ft. 6x tippet - weight in the middle - size 14 tungsten beadhead.
I use this set up quite a bit when I want to get my flies down quickly, especially when I'm fishing midges in fast water. Midges don't have much weight and tend to float above some fish heads so the weight brings them down quickly while still giving them free movement. Key is to use a little longer tippet when tying on the dropper so there is enough tippet between the fly and the weight so you still get a natural drift.
Just watch your casting...the weight will really cause a birdsnest if you aren't careful. Roll casting is not your friend when you have this much weight on.
Split shot has helped my fishing a ton. The big hogs don't like to go very far from cover or darkness...
If I can't get the rig deep enough in the hole, sometimes I will try to drown the whole setup upstream of the pouroff into the hole by several feet or more. This results is snags at hydraulic reversals sometimes, but if you can get the mass of the nymph rig into the plunging water entering the pool with a bit of slack, sometimes this tongue of water carries the rig much deeper than simply letting it sink. (besides, the fish are eying that tongue of water for goodies to be dropped into the hole).
I learned this after getting frustrated one day with a shallow dry dropper setup. I drowned the whole indicator and all in the upstream tongue of water, the whole leader got sucked deep into the hole, and suddenly I had a nice 14" brown on the end (it went for the drowned stimulator right below the pouroff).
Edit: even though a #10 stonefly or 20"er nymph may not be on the menu, they are good heavy nymphs that will drag other flies down if you are fishing someplace where fish are spooked by split shot. Also, supposedly flouro tippet is more dense and sinks faster (as well as being more transparent and $$$).
I have and still use split shots as well, as I don't like to tie a bunch of weight into my flies, but I have recently been tying up some weighted scuds/czech nypmhs.
I don't have any real issues with Czech Nymphing, but I am not a "practitioner", I have however researched it, and tried some of the setup techniques on stillwater, and I am thinking about trying a similar set up on the river under an indicator.
What I do is run a sinking furled leader (Joni's kevlar brand) add about 6 feet of 6# mono, then about 4 feet of tippet, tie a small loop in the tippet about 18 inches from the end, tie 6 inches of tippet to the loop and add a weighted fly. At the end of the tippet, add an unweighted fly. This fishes well from a float tube, seems to cast ok without getting tangled, and gets both flies down around 6 or 8 feet (when slowly kicking your tube) and has been quite effective for me.
Using the same rig (this is my plan), I am going to add an indicator and fish the fast side of the seams on the river, with short strips back on the slow side, or possibly just short line it, cast accross and let the line work down, then flip it back up and accross again.
As well as this rig works on the lake, I am thinking it will be effective under an indicator as well, it should get both flies down in the water column, and except as I noted previously, if you are in slow water you may lose contact with the trailing fly.
If I get a chance this weekend (storm blowing in) I may give it a try on the Truckee to see how it works. I suspect this would work best in faster water, but you will need to set the indicator right so it does not hang up constantly.
After reading about czech style, I adapted one of the principles to more standard nymph drifting.
With a czech setup the light fly on the end serves to keep the heavy weighted nymph out of moss and snags on the bottom; however, it requires a ton of knots and an extra tail of tippet that is annoying sometimes (wind).
I started putting a buoyant fly below a heavy tungsten nymph on single line 3 fly setups. Typically I will use a San Juan worm with floatant at the end. When doing a dry/double dropper setup, this creates a sort of 'hammock' effect, with the dry and the floating nymph supporting the sinking nymph. This seems to keep me out of the didymo moss better, and still gets the nymph toward the bottom. Play around with various buoyant flies for t he end to achieve the desired effect.
The extreme end of this is fast deep water with moss and snags on the bottom. I end up with contraption rigs like: Indicator/shot/tungsten nymph1/double shot/tungsten nymph2/buoyant fly with floatant. Its a total mess, but gets the job done. I managed to have dozen fish afternoons last spring in the 'chocolate milk' flows that no one was fishing using this style with flashy nymphs.