Size 16 Elk Hair Caddis ???

Last night I tried tying up some size 16 EHC's. Being that I was using a
size 16 hook, I opted for 8/0 Uni-Thread. I couldn't put a whole lot of
pressure on the thread to secure the elk hair without breaking the thread.
What size thread would be recommended to tie these?

Trying to comb out the underfur from the elk hair was a pain in the
uknowhat. Any suggestions?

Also, what color bodies work best? I used a light olive and a coachman brown
hackle. Would a tan body work better? If location is needed to determine
types of hatches, I'll be fishing in the upper mid-west.