For my 2 bits worth, I'd go with the P. I think the balance and feel would be off with a PM grip. Grip is important.
Course I'd probably just leave the TP as is and get a PM45 as a running mate which of course isn't on the list of options in your original question.
Sounds like a fun project anyhow.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."