The Metalform mags, which were made for New Detonics in Phoenix, can be made to work in most cases. They were reasonably close to the second generation mags that were issued from the Seattle/Bellevue factory. (The ones that said, "Detonics 45 ACP" on the bottom. Not the ones that said, "Detonics 45 Auto"). I've seen some Metalform mags that lock in and work well. I've also seen some that don't.
Careful filing of that "little ridge on the baseplate that is hitting the mag well of the gun" is the solution to your problem. Don't do anything to the mag catch notch. File the ridge(s) only enough to allow the mag catch to engage the notch without having to bash the magazine into the frame.
If you don't have good manual dexterity, let an experienced "smith" handle it for you.