Gentlefolk; I am new to Glocks, but owing to an ongoing sale at my LGS, I have accumulated more than any rationale share of them. currently this includes a G21 Gen2, a G23 Gen 3 and Gen 4 and now new to me, a G17 Gen3. Of those, the G21 Gen2 is the most comfortable in my hand, with the G17 Gen3 next. Least comfortable are the G23s. So, I thought the backstrap options of the Gen4 would give me a perfect fit...but...I don't know what a perfect fit might be. I am not a fan of the rough texture of the Gen4..I find the older finishes more comfortable, but I am not really into the extreme retrofitting that some folks here apparently can do. So, my question: how do I know when a pistol fits, and which size should I settle on with my Gen4 G23? I don't know how to describe or analyze my hand size. Physically I am 6 ft 210 lbs. Right-handed, if I fully extend my hand, I just cover the width of an 8.5x11 inch piece of paper. This means the edge of my thumb is on the left margin and the edge of my pinky is just touching the right margin of the paper. With no grip on the Gen4, my hand wraps easily around the entire grip but my middle-finger nuckle is then right against the bottom of the trigger guard. However, the trigger falls into the first joint of my trigger finger... The middle strap seems the least comfortable. The large grip fills my hand nicely, but allows my hand to move around more..I can select the type of grip I can have, but I don't know what that grip should be... Back to my question then..how do I know what a good fit is for me? Thanks all!