This is on the Mac correct? And you have confirmed that Optifine is indeed installed, and functioning correctly? If so, I eagerly await your tutorial, so that I can give it a try!
I agree, I have been trying to get Optifine into Hexxit since late June…because of the issues with Hexxit/MC, Optifine & Mac (lag is the killer) I have essentially given up trying to play Hexxit. So anything new that can be tried would be really good!