1. I don't think open N DB instances for N d3 accounts is a big deal. Just run them there, what's the problem? Is your machine short of RAM or what?
2. I can set. I changed Barbarian.cs in Routines/Belphegor/Routines for my spell build in just 2 minutes. Now it use leap/revenge/ignore...
fps drops only when you are not choosing d3 window as the most front window. On my machine if I put DB in front of d3 window fps is horrible. But if I minimize the DB window and click d3 once then everything is OK. I'm using gtx580 1.5g ram version btw.