If you are staying 60% at Hamptons and switch to SPG you will no doubt end up staying in real dumps with SPG and driving way out of your way to get there.

Did the SPG thing for seven years as a Plat. Check the SPG offerings where you travel to, look at the rates, and also look at the distance from your appointments. I am 90% sure this will not workout for you based on the info you posted.

MR is a good choice as they have slightly more hotels than Hilton and many price options.

MR and HH by far each have the most hotels. SPG and Hyatt are substantially fewer. Also, there are quite a few defections from SPG in the last year or two. It's not the program it once was although it has a very vocal following here at FT.