I am looking at a G40 MOS. The only issue is, I had a Gen 3 Glock 20 and found the grip too big/didn't fit my hand so I sold it. I recently got a Gen 4 Glock 22. The frame is different than the Gen 3 (smaller/different something). Was wondering if anyone has tried the new G20/21/40 and how does the grip compare to the Gen 3 models?