I actually bought the full-size Altamont grip. My GP100 is primarily a woodsbumming gun. I'll sometimes engage in some "covered up" carry if I stop at the Trading Post on my way back from hunting, out of politeness, but even if I were to openly carry it would be unlikely to cause consternation.
I do have a Simply Rugged holster with the IWB loops, and I'm contemplating taking the GP100 on this weekend's eastern WA road trip. The fullsize Letts style grips hide better than the Match Champion grips, but its is still quite a bit of gun to cover up.
So @JohnInWA will have the compacts, and I'll have the full-size from Altamont. MOAR SCIENCE!