I'm going to purchase a 10mm Glock. I plan to purchase the G20SF model. Will the G20SF be compatible with G20 mags also? Is there any reason why I would want to go with a G20 over the G20SF? Afterwards, I plan on purchasing a drop in .40 barrel. Any suggestions as to manufacturer's. This will be for hiking / back up hunting, not a target pistol. Thank you in advance.