I like to have part in hand personally. To make sure it fits halfway nice and covers desired area.Right on. From what im gathering frome everyone is you'll get the feel for the spot weld cutter and its capabilities. Just gonna have to dive in. I was gonna cut the pan out last night but i dont have the replacement in front of me. My ? Is should I wait to make sure I don't cut to much out? Or go ahead and cut to the factory welds? Also should i save as much good metal as possible or cut it all out uniform and neat the same size as my replacement?
As far as how much to cut double edge sword.. If you just cut cancer out of car u have to cut replacement panel to fit. You cut car all out to fit whole new panel you cut once.. there will be a TON of opinions to make a whole thread over that debate. Take all the opinions and what you learned and do what works for YOU. After I finish up my header panel, I be off to the floor pans like you...