"I suppose that with such lighter loads the possibility of shoulder setback looms its head, so segregating cases might be advisable."

It is advisable to segregate cases with powder puff loads in high-powered rifles because of shoulder set-back.

I've used 10 grains of Unique with both a 150 grain fmj and a 169 grain cast lead bullet (Lyman No. 311413) for short range plinking loads. After working them up, I found it was something that I never really put to a lot of use but it did make for entertaining shooting that wasn't much different than shooting a .32-20 rifle.