So... have these instructions actually been useful to anyone?
I was chatting with turtle in-game, and even though he followed my steps, it seems that Optifine was still having serious performance problems for him.
One thing you may want to try if you're also having issues with Optifine is experimenting with the different editions of Optifine. The developer releases standard, ultimate, light, and sometimes more versions. It's really unclear which is supposed to be the best for any given environment. So, experimentation is almost mandatory.