stripped butterfly retaining screws

Got a couple of stripped heads on the butterfly retaining screws. I got may shaft seals in and new retaining screws in from chacal. The retaining screws on one of the carbs were pretty well stripped. I filed down the ends to remove the peening. Used the screwdriver from chacal for japanese phillips style screws to try and remove. Previous stripping was too much and couldn't get enough grab to turn the screws. What's my options to get the stripped screws out?

 

Buy a reverse-twist drill bit, size is just smaller than the threaded hole, drill out in reverse, then chase the remaining threads with a Metric tap set available at Harbour Freight for cheap.

If you get lucky - the drill grabs the screw and pulls it out clean. So lube it.

Use Loctite on re-assembly

 

Wool hoop. Got them out. Decided to use an easy out. I had one with a tip about half the size of the screws. Put the carb in a vice between a couple of pieces of plywood and slowly and carefully drilled with a bit as small as the tip. Slowly turned and as it grabbed I heard them snap loose and the spun right out.