Steve, I have been using 4.7 grains of Unique behind a 158-grain SWC in .38 Specials such as 2" Colt Detective Specials and S&W Chief's Specials. It shoots to the sights and is managable with the factory-issue grips.
A lot of the lighter bullets do not land anywhere near the point of aim--usually they impact low.
Unique meters poorly out of my old RCBS Uniflow measure. But it meters well through the measure on my Dillon 550B.