Stupid Bed Bolts

[Turbo85GMC]

I'm trying to take my bed off for a c-notch install, and out of the 8 bed bolts, 4 of them spun. I was able to get 2 of the spinning ones with vice grips on the heads up top. Now I'm stuck with the last 2 up near the cab on the driver's side. I cut slots in the heads to hold them with a big screw driver from the top, but the screw driver wouldn't hold. I don't have a welder or I'd just weld a big nut on the top and use a breaker bar.

Unless anyone has any bright ideas, I think I'm down to just drilling out the head and punching them down. That should at least let me get the bed off in one piece.

When I go to put the bed back on, does anyone have suggestions on how to repair the "rounded" holes in the bed floor? Do I need to have some washers with square holes welded to the bed floor? Or do they make bed bolts with like an allen hole in the top?