as for replacing the hammer with an after market unit then my concern would be
1) are you of the ability to replace the hammer and make adjustments to it for it to be safe and reliable?
Hammers are typically NOT drop in units as the bottom end (notches) generally require fitting to the sear etc.
2) I am not sure IF a spur hammer will clear the high Beavertail grip safety, you may not be able to fully cock the hammer for lack of clearance?
I can't answer this question so maybe one of our 1911 Gurus will be along to help you with that.