I’m at the point in my restoration project where I need to install right half floor pan. Since my resources are limited, I need the quickest and easiest way with the least amount of time spent under the car.
Floorpan is welded to the tunnel (left) and long (right). Don't I still have to cut it under the tunnel? Should I cut along center line and butt weld or leave a couple of inches and lap weld new floor? As alternative to drilling spot welds - can I cut it along the tunnel on both sides of the spot welds and along the long and weld new floor on top of what’s left.
This doesn’t have to be concourse, just have to look somewhat decent and more importantly be sturdy. Any suggestions and pictures are greatly appreciated.

Take a look at your replacement piece to see how far towards the center it goes.

I like to rough cut all the stuff I am removing to get it out of the way. Then you
just need to remove the spot welded strips.

There is usually a lot of rust between the old panels. Removing the old pieces by
drilling the spot welds, or by weakening them with the edge of a cutting disk and
then breaking them loose will work much better than trying to weld over them,
especially upside down. All that rust will cause a lot of splattering and bad
penetration.

If you can flange one side then overlapping can work ok.

Remember there is a lot of stuff you don't want to cut inside the tunnel.

John