Instead of just a simple hammer notch, make it follow the circumference of the hammer by a bit more than the amount of travel needed for a notched safety to operate. If that were cut true, it would work nicely.
Right on
UC. I planned to do that because it would facilitate using a safety notch at the rear of the cocking bar slot.
I would also be sure the only place the trigger bar contacts the sear bar is near the aft end. I'm thinking too much contact along those parallel surfaces would make for somewhat erratic function, especially if any debris gets in there.
I tried that with a model. The geometry and mechanics didn't seem to work well and for some reason I don't quite understand required a longer trigger pull. The slide fit worked beautifully. I've considered putting a teflon coating between the two. But they should fit together tight and should slide well with a good polish.
A small set screw in from the side of the trigger bar to keep the adjustment screw from moving might be a good add.
Good suggestion
UC. Keep them coming.