DRJ,
If this were my gun , I would get a paradox mold or some sample bullets cast no harder than 20to1 and about 730gr. I might even try pure lead. I would have sizer made that would size a bullet to the point you could push it through the bore with little resistance. I would also want to be able to size larger than that up to around .735 at various diameters. I would use the the pressure tested Unique load CAREFULLY starting under 21grs and shooting over a chronograph looking for a velocity of around 1050fps to 1150fps. I would assemble the loads in the same manner as any Westley or Holland paradox starting with the smaller bullets. But I wouldn't and couldn't advise anyone to do this other than myself.