I understand that, but is it really needed? Once drill open the flash hole, it is pretty much a dedicated brass and better separated from the regular brass.The primer is being used as the propellant since there is no powder. The larger flash hole vents the primer explosion forward into the case more efficiently.
Also if shooting in a revolver not drilling the flash hole could make the primers back out and lock up your gun. Hot glue bullets are a blast.
I tried the wax bullets tonight. Admittedly, it was crude. I jammed a primed case into the flat of a candle, twisted to break it, chambered, and fired. But it did let me see that it is something that I can do in my workshop, won't wake the neighbors, and I can help my boys get over their flinch. With a little more work on making them uniform, they should be good training. But, the glue looks like it should be even easier to make them uniform, so I am also pricing a mold...