YSR80 Fuel Help...

My YSR80 has been a long time in the build mostly because I'm lazy and have too many other projects. However I'm will soon be getting it put on the road, I'm just wondering a few things:

What octane fuel should I run? I've been using 91 but a friend of mine who is in to motorcross said that you should only ever run two strokes on 98?

When I was first learning how to ride, I once changed down instead of up at the top of 3rd gear, have I done terrible damage? I grabbed the clutch pretty quick but not before I had time to watch the tacho shoot well into the red.

The bike has never seemed to rev out completely to red line and seems to struggle a bit at the top, is this a fuel issue, a carb issue or something more major?

It doesn't seem to charge very well, does anyone know the correct battery charge rate?

No one can tell me what fuel to run?

I don't have a YSR80. However, of all the 2-strokes I have and owned, I've only use the highest octane pump gas available where I live, 91 octane.

I know some guys have used the lowest, and claim they didn't feel any difference *shrug*

i use 93 in my YSR80 and never ahd an issue.

I use Cam12 race fuel mixed 50/50 with 94 oct. pump fuel. Works great and I can tell a differance for sure!!!! This is in my NSR50 with 63cc kit