:grin: Just so you know: GLOCK recommends the use of, 'Gunscrubber' and, 'BreakFree CLP.' If you own other firearms, watch that, 'Tetra' around wood finishes. I, almost, ruined the grips on a vintage S&W Model 41 with that stuff.
There is no, 'Slide Release' on any GLOCK pistol; so, don't bother to buy an extended one. Those things are a solution for a non-existent problem. The part you are referring to is, actually, a, 'Slide-Stop.'
The correct way to charge a GLOCK pistol is to, first point the muzzle in a safe direction, then, reach across the top of the slide with your other hand, grasp it firmly at the rear and smartly pull the slide all the way back. Next, let it go!
Occasionally, you'll meet a shooter who does not do this; he's the one with a, 'Slide-Release' on HIS GLOCK; and you can bet your last dollar that he's never trained to fight for his life with this Austrian, black plastic, wonder pistol!