I'm going to be the heretic in the group that DIDN'T match drill these. I ran a drill through the
prepunched holes, deburred and THEN bent them. Oh my...it'll probably fall out of the sky
I just decided for myself that whatever horrible effects there might be from not match drilling them would be overshadowed by the mess I'd make trying to debur them after they're bent. As always, do as Vans says, not as I did...