Is there much difference between 75.6 and 77.8 gear inches feel wise? will I have to adjust a lot? does 2 gear inches make it that much harder to skid?

Yeah you will feel the difference. Will you have to adjust alot, I am not sure because I don't know how strong of a rider you are. Probably a little until you are used to the new gearing. It will be harder to skid, but not impossible. Skidding depends alot on weight balance and location over wheels. Being strong only help make resisting the pedal rotation easier.

when i went from 73 to 76, it seemed like a big difference and took a while to adjust, but when i went from 76 to 70, it didn't hardly take any adjustment, and just felt good.

Well, I can feel differences of just a few gear inches on my daily commute route, because I know the route so well, the slope of the hills etc. Do small changes in gearing prevent me from climbing hills or dramatically change my average speed or ability to slow down? Definately not. For me something in the low 70s is great for leisurely riding or in a dense urban environment. I like 75-76 inches for fast road rides (with hills). I like 80+ on the track. If you just put me on some random bike on a road I've never been on before without any kind of cyclocomuter, I probably couldn't guess very accurately how many gear inches I was riding.

2.2? Sorry, but somebody had to be a jerk!

someone always has to aparently.

edit: if you take into account variability in tire size it could very well be a difference of .2 inches.