72 Scamp and 440 Work in Progress

work done today. I got the floor in and lined up pretty good. Problem is getting all the holes to fit flush so I can weld.

I have a few questions with some of the holes its going to be impossible that I get them flush enough to weld. Would a combo of welding screws and rivets work ? I want to make sure its done right but. Not to metion some of the holes on the donor pan are HUGE.