No rush on it, I know you’ve got a lot going on right now. I’m sure there are uses for program stops that i’m not thinking of right now, but for what I can think of right now you have already added another method for dealing with it, or simply its not needed. For instance, the Z-height changes, or removing/adjusting parts after they have been cut. I’m sure that, at some point, I’ll find a need for it and then I really will need it but nothing is coming to mind right now.
Most of the M codes don’t really apply to the Maslow, anyways. The only ones that I think could come in handy would be M0, M1, M2, M3, M5, and M30. M3 and M5 would go along the lines of another thread about allowing G-code to turn on the spindle.
I learned to machine on a Haas Mini-mill where you had to spell everything out, and my style of programming will probably reflect that a little bit.
EDIT: Found the other thread, linked it for reference