watch ebay for old style Boreal Firey's from 80's. I see them every now and then, brand new yet, going for like 30 bucks. There is a pair of size 5's right now on ebay tonight. More show up on occasion. Sized true to your street shoe foot, come extra wide and fat toed. All leather so they stretch out easily too. I wore a pair for years long ago and they now are 2 sizes bigger and my thick winter sock climbing shoes for cooold days. Otherwise a pair of 5.10 Pitons, oversized and they might work.
Fires are way old and the rubber will likely fall off. Better luck with Boreal Aces. Really well made, and the reddish ones aren't THAT old. Get 'em wet and they will stretch out to any width.