I actually had on slip on buckaroos, which I still own, and they fit correctly with a slip in the heel... I don't know what happened, I think I got knocked out and came out of the stirrup pretty quick. Hard to say... can't quite recall. Also I had aluminum barrel stirrups with grip on the saddle... I was pretty much hung up every way possible.
Like I said... 100% my mistake though. I'm an idiot.