The only 3/4 oz load I have using Unique comes from Ballistic Products Inc:
WAA hull, fiochi 615 primer, 1 20ga Nitro card+1 SG20 wad, 18 gr unique, 3/4 oz shot, 1220 fps
I haven't tried this and so cannot comment.
I have tried and like:
WAA hull, Win 209 primer, WAA 20 wad, 12 gr international clays, 3/4 oz shot, 1150 fps
This load is pretty forgiving, and also works with remington STS hulls and Rem 209 primers.
FWIW
tq