Have you tried this? I needed to free 4 trailer brakes frozen to the drums. I grabbed a mallet and pry bar and as an after thought, a bottle of air brake anti freeze/alcohol. I just splashed the alcohol onto the shoes, it ran down between the bottom shoe and the drum, and on the top it kind of seeped in from the side. The bottom popped loose on it's own and the top freed with one smack!
That is interesting I have an axle shaft from a 9" ford cut flange off I stuff through hole in wheel and rapp with a manny sledge works pretty good going to have to try this trick of yours