I have diamond shaped punches and I punched through 9oz saddle leather and through buckskin backing on the other side no problem. You can make whatever sized hole you want to, the awl is to make the hole big enough to get your saddle needle through. It will shrink somewhat back to the original size of the hole. This set works really well for me
If you're just getting started, this kit is a good deal. Still my daily driver.