I've got some trouble with nuts...

I need some info. on the removal and instalation of a new nut in strats and Teles. I get regular fender replacement nuts but I think they need shaved down. I tried to replace one in a tele but after it was installed I had real trouble getting the guitar in tune, the action is nice but for the most part it's untuneable. Plus I had trouble getting the old one out, I didn't damage anything but it was a struggle. If anyone can tell me how to do that, it would be beyond the realm of the gods...
And if anyone out there could get me a wiring sceme for a strat that a moron could understand that would be great. I need to clean out and rewire a strat.