I've hesitated to respond because there's a Hodgdon lead recipe I've adapted to No. 4 bismuth---"finding out for myself"---and I don't want to get into the weight/volume conversion controversy. My opinion is pressure/velocity should be equal for bismuth and lead: same weight shot and powder and same primer, hull and wad.
All cautions offered, I've had good results with the Hodgdon 1 3/8 oz recipe from its 2003 manual of FGM hull, Rem 12H wad, 28.7gr Longshot, W209 wad, velocity 1185 and pressure 6900. (See above re adjustments.)
Another 2 3/4 12ga 1 1/4 No. 5 bismuth load is Rem-Pet hull, Windjammer wad, 17.5 700-x powder, Rem 209 hull, pressure 7600, velocity 1145. I use both in my dear old American classics, pleasure to shoot, no complaints.