Honestly the only other plug that i would run with the grp is the OD77t or OD97t, i know some guys have used os plugs, but once you go that route you have to stick with them from what ive heard. I had the same problem where my LHS could no longer get grp plugs. So i went with the OD77t and have not had any problems yet. I actually think it runs better to tell you the truth.

Good luck man!