Drivers floor pan replacement

I'm working on this floor pan and have two questions. #1 Which is better trying to butt the old to the new and stitch welding or overlapping them and welding on both sides? #2 The new panel fits good front to rear . I have to keep it to the left for the door gasket channel..this is where the problem begins. The gap by the transmission hump/tunnel has a gap of about a half inch. Am I doing something wrong or do you just beat it into submission? I do enjoy my hammers! TIA, Rick.

Is this a show truck? Butt weld would be best but I think most people lap weld. Flanging the patch would look better then a lap welded patch. I'm still planing on butt welding my 78 floors, but that might change.
as far as fitting, get the hammer out, I'd line up the ribs in the pan so it matches and then "hammer on dolly" to strech the metal to meet the tunnel.

My welder, younger brother, agrees on the fight and hammer to obtain a butt weld. It'll be hidden by the floor pad so I'm not really concerned with appearance. Anyone that crawls under to critique the work had best take into consideration their boys are in a vulnerable position......

Never do an overlapping weld on a car if you can avoid it. You are just creating a nice pocket of moisture to rust through in the future. Get the metal lined up as close and tight as possible and butt weld.