Recently someone was asking this same basic question in a different way under a different subject title, and I thought that a more focused title might help those looking for a possible answer to this question.
Here's my thoughts, but I'm sure those that have more experience with 2 and 3 finger style can add more information..
Without the use of a resonator, you need a tone ring that adds some punch and clarity that helps the two or three finger picker be heard. I would suggest a whyte laydie or tubaphone ring or perhaps a Silver Bell tone ring. I recently picked up a Bacon Blue Ribbon inspired banjo and the tone ring in it is especially good (to my ear) for finger picking. Another thought is a top tension style banjo..
