Replacing Tuner heads

I really love my Les Paul but I really do not like the tuners.

Not only do they seem cheap and plasticy - they also don't handle fine tuning very well at all and also the G seems to go out of tune loads.

Reading up a little on changing them I note that the G string issue might be the nut rather than the tuners?

Anyhow I ordered a set of planet waves tuners which have a ration of 18:1 and also clamp the string and automatically but off the loose string so it doesn't have to be wrapped around and I don't have to find anything to trim it.

So all in all I was happy to have found them.

Last night I tried to fit them and disaster - the holes are currently smaller than the required holes. and whats more, I have gouged some of the paint/varnish in trying to get the old one out. Totally gutted!

So can anyone advise on the best method to make the hole bigger and whether I should actually attempt this myself ? Also how easy is it to repair the damage that I have done? It is quite minor but major to me!

Cheers