I notice that Crimson Trace says the LG-617 will fit the G20sf and G21sf. However, resellers don't list it as fitting either of them. Anyone own one? How is the fit on the G20sf? (It's odd that the same laser sight the fits the small bodied glocks would fit the big boys). Is this a good buy and $200? I like to aim, but lasers are better. Wanna kill these ads? We can help!