Hole size for floor pan spot welds...

I think my spot weld cutter makes a 5/16 hole. Any I added were at least 1/4. Always start the weld on the heavier metal under the pan and be sure its down against it. I set a cinder block on my front pans to pull down and hold it tight till I got a few welds done. As best I could measure, both original and replacements from Year One were 20ga.