Early A floor repair options?

I'm in the process of dealing with my floor pans soon..just started to remove interior and caught a glimpse of the Swiss cheese beneath the rug...My question is do I have to weld a brace in by the doors when I start to cut the floor? Probably cut one side at a time from front near firewall to before hump in under backseat.

First if you plan on replacing that much in an early A be sure to find a good used pan as a full pan is not made for them yet. I bought a whole parts car for full pans in the past.