I like to use flathead screws because the machining can be done with one operation instead of three. For example on a pan head screw you would have to
I would just counter sink the holes to proper depth, with the proper machining equipment it's the easiest route. All solutions are a matter of perspective.
you don't do it on flat head screws, you'ld do it on panheads, just like i did on the blue 'mag posted here. standard 1911 grips usually can't fit the