Howdy...
I used to do a lot of leather work. Your best bet if using the osborne type punch is to work on a wood top surface with a dense rubber mat, conveyor belting works real well.
The drill press methon with the revamped hole saw works, BUT I caution about loosing your material andhaving it spin and cause injury to you.
I have a revamped holesaw that I place a 7/16 deep socket over, 1/4 drive, and connect that to an old door knob with 1/4" keyway stock. I can cut 12 layers at a time with no effort, just a 3/4 turn down to the rubber.
4 cuts, 1 stack of 48, run a needle and thread thru it. I lube mine in bulk and squeeze them out and then peel them off the thread as I need them.
Brett