Sheet metal backing for body work question

[bluesmokennoise]

Attempting body work on a 91 Pontiac Sunbird LE cutting out the rust on the outer door panel. but have neither equipment nor expertise using welding gear. My plan is to just affix sheet metal to the inside of the door panel with seam sealer, then apply self-adhesive metallic body patch followed by body filler, smoothing, sanding and painting. What kind of sheet metal would you guys recommend to use that is primarily just a reinforcement of the body patch and body filler? Galvanized? What would be best? I am somewhat concerned about the rusting. I'm also replacing both power window motors and the rust I discovered inside was staggering so I am not wanting to do this repair using the wrong kind of sheet metal.

 

[92 Sunbird LE]

20-22 gauge, galvanized is hard to stick paint to....sand it up good for filler to stick, , prime bare metal with spray can etch primer for the inside , then undercoating or Bedliner spray cans.....

Doug in P.R.

 

[bluesmokennoise]

Thanks Doug. I had a feeling I could count on you! By the way, I sprayed the ash tray to match and it looks
terrific.