Trunk pan replacement

What is the best way to replace a trunk pan?
Overlap and spot weld or but and weld complete?
It's a 67 caprice if it maters

 

The best way is to butt weld, then you will have no seams and nobody will ever know you were there, the overlap would create a space for moisture to get in in eventually rust out your seam.

 

I was going to do the perimeter as a but weld, but the center piece is flanged on each side and I was going to spot weld this. It's a three piece replacement pan. Will that be good?