www.megadrum.info

I started by just willy nilly assiging notes until whatever VSTi I was using worked and than saved a config named for that VSTi.

I'm leaning towards using the Roland TD20 as a universal midi note map because I see many VST's seem to have a pre-made note map for it.

Is there a drawback to this approach?

I think it is really up to you - whichever way is more convenient for you.