Welcome, I've found that if the drums have been on for a long time they can be very difficult to get off period. Your on the right track, after backing the adjust off I "hammer" on the drum while pulling and prying. I think the old shoes wear grooves in the drum and you have to get the drum to clear the shoe. You might want to make sure your emergency brake cable is not holding you up. The other problem is the wheel cylinders are frozen up and the shoes won't back off. Cussing and hammering has always worked for me.
