Universal Clays and Alliant Unique are ballistic twins. 4 grains of U Clays and a 115 grain cast bullet should produce a fairly mild load. My standard revolver load for the .32-20 uses a 100 grain Cowboy bullet and 3.2 grains of Bullseye which gives a MV of about 760 ft/sec from a 5" barrel. In the past, I have used 4 grains of Bullseye which produces a little over 1000 ft/sec. I wouldn't worry a bit about your using 4 grains of UC.