Okay, I decided to play Pokémon Crystal (by.....alternate method, since my cart won't save anymore) and I'm having a real tough time trying to find Heracross. I do know it's in the trees you have to Headbutt, but where's a pretty good location to find it (and what would be its appearance rate, hopefully not in the single-digit percentile)?

Thus far I've been pretty lucky in finding stuff, but Heracross seems to want to be a problem...