Unique don't start working it's best in the 45LC untill you get up to 8.0 grains, and that is assumeing that we're talking about using a 250ish lead bullet. A lot of guns like 8.5 even better.
I'm a big fan of LEE's 252 SWC bullet, Alox lube, Winchester WLP primers and a heavy roll crimp over 8.0-8.5 grns Unique. In fact, that has worked so well for me, for so many years, and out of so many different guns that I'd go so far as to say that if your gun won't group with a load simular to that, that you got's some mechanical issues that needs tended to.
Can't help with the 38/40 or 44/40 though, because I've never owned one.
DGW