Hence my new pair of boots! I found these heeled boots in the Bedford Ave Salvation Army. You can kind of see in the bottom photo how the center seam on one of the boots was busted open. It seemed strange given that all other parts of the boots were in fantastic condition.
Ultimately the rip gave me a good excuse to crop them at an angle. To add the studs, I pushed the open prongs on the back into the leather hard enough for them to make an impression, then used an awl to pre-punch the holes. After inserting the stud's prongs into the holes, I secured it into place by using needle nose pliers to bend all of the prongs inward. In some places, the leather seemed slightly stressed from this, so I put masking tape on the back side of the leather. Once I'd finished studding the boot I just ripped the tape off. The extra bit of stability the masking tape had added was enough to prevent the leather from stretching.
The whole process was much more time consuming than I had anticipated, so I'd recommend a glass of wine and a long ass movie if you're planning to add this many studs to a project. They definitely made the whole process go by MUCH quicker.
*needle nose pliers