I normally tie on 2/0 hooks. Gama now has them in a 4/0 version. Normally I don't go bigger than 2/0 because I get alot more snags in the shallow rocky water I fish.
I have a couple of different flies I use now though. The bodies are all the same but the epoxy heads are different. A very small epoxy head allows the fly to float until pulled under the water. A large head sinks. I will make some up with both hooks and see how they work.