I'm a brand new shooter...I haven't even figured out a grip that works well for me, but I did figure out how to hit the mag release easily! I'm a fan of using my right hand, middle finger. My hands are pretty small so even with an extended mag release, there is no way my thumb could reach it on my cz duty or my boyfriend's 1911. He couldn't understand how it was possible until he watched me do it. It barely takes any movement; I just extend my finger a bit, keeping my index finger on the side of the frame (for resistance, and safety of course). To hit it with my thumb I would have to loosen my grip and roll my wrist.
I practiced reloads for a while, obviously to improve, but also because my mags were only popping loose, not dropping. Once I switched to using my middle finger, and after much repetition, the mag slides right out. I got it down smooth enough that my boyfriend thought the mag fell out on its own