Well...I'm hoping you wouldn't compress kick and snare on classical. I hope you wouldn't HAVE a kick on classical. I hope you wouldn't bring a compressor near classical music...

If you're going to compress the individual components of a drum kit, I like to treat all instrument groups within the kit as separate entities. Toms get their own compression, snare gets its own (top and bottom usually similar), kick its own and overheads their own.

That being said, I rarely ever do it that way. My preferred method is a minimal mic'ing technique where I get the whole kit with 3-4 mics and then use appropriate compression on a bus for the whole kit. Typically I'll use an opto compressor on the drum bus with minimal settings, so I'll set the desired output gain and then push the drums into the bus until I get the desired sound.

Cheers-
J.

It really depends on the drum and performance more than the genre. Sorry to say but you really have to trust your ears.