That's a square load and I would certainly try it. If I were hunting I would go as high as 4 drams with 1 1/4 oz. depending on what I was going after.
For clay targets you should be fine. With repetitive shooting I like lighter loads shooting black powder(or I get a headache...). I just shot my 10 gauge lifter with 2 5/8" brass shells at the Southern and I didn't really have time to load new shells and used what I already had.
I was shooting my "light" 10s that are 2 3/4 drams and 1 1/8oz. of shot. I did much better than I would have thought and hit 21/25 at the heritage shoot. And was reminded how much fun it is to shoot black powder shells