A drill and some T-Nuts. That's how we did it back in the olden days, when shoes didn't come ready drilled.
Back in the olden days you weren't prone to putting drills through your hands like the fumble-fingered, flabby yoof of today, though.
How stiff is the sole?
Very! Rigid plastic. It's got a metal plate thing in the middle bit as well with a square nut that can be adjusted left and right. Assuming I did decide to drill it the holes would need to go where the plate is now so it'd irredeemably weaken the sole, I think. I'm going to need some proper, newfangled shoes, aren't I?
Back in the olden days you weren't prone to putting drills through your hands like the fumble-fingered, flabby yoof of today, though.
Very! Rigid plastic. It's got a metal plate thing in the middle bit as well with a square nut that can be adjusted left and right. Assuming I did decide to drill it the holes would need to go where the plate is now so it'd irredeemably weaken the sole, I think. I'm going to need some proper, newfangled shoes, aren't I?