Welcome to the 640-1 Club!
As far as grips go.......I tried these stocks first. Carried well, but the recoil was a little less "fun" than I really liked:
Then I tried these. Looked and felt great, but seemed a little too nice for my daily CCW:
I finally went full circle and switched back to the OEM Uncle Mike's. The feel perfect, reduce felt recoil and don't print even with pocket carry (for me):
Congrats on the 640-1 and good luck settling on the just-right grips for your needs. Try the UM's if you haven't yet!