The obvious solution to the nitro bleeding problem, if it really exists, is to
never store your powder at high temperature and humidity no matter what its composition is.
VV has some good reloading data on their web site:
VihtaVuori. I have used several of their powders in light 45 Colt and .357 Mag loads and find them to be relatively clean burning. I remember seeing a picture of a cowboy action shooter at one of the meets (Trail's End, I think) who called himself "The VihtaVuori Boy".