That is an awful lot of blind manipulation of firearm and like NP stated just stick it in your pants.
That said, I have a couple of holsters that I might consider using something like this with when I am in rough country crawling about in the brambles. Couple of places I carry military style full flap holsters and they still get snagged and opened. Not sure on the barrel plug, maybe a little kydex cap to fit over the pistol or just attach a bungee strap to the parent holster. Regardless you end up back in the dilemma of securing the weapon vs speed of access.
A thousand reasoned opinions never equal to one case of diving in and finding out.