According to the 3M site they claim their panel adhesive is 11 times stronger than welding if done correctly. I use both MIG welding and panel adhesive in my bodywork repairs and sometimes both in one repair. I had to do a floor panel repair in the same place your talking about and I welded the metal for this repair for both the floor pan and cab support. When I replaced both my cab corners and the lower back edge of my cab I used both welding and adhesive to make these repairs. Here's a link to some photos of these repairs: