Like previously mentioned, I wrote out about 50 pages of lessons to do with fingertapping.

There's a definite advantage to using compression and distortion and maybe even a little reverb. However, once you get your finger strength and speed up you shoulnd't need it as much.

What I usually do is set the compression threshold high so that it keeps the notes on an even volume...even when using no distortion.
You want the notes to even out and then gradually decay.

If you get full access to the lessons you'll get a better idea of what I'm talking about.

Cleanliness and even tapping is the key more than anything.

There's another lesson using a clean sound and reverb to do "Somewhere Over The Rainbow" in one of the lessons that might give you an idea of what I mean.