Sheet metal repair?

[jmbrodsky@domain.elided]

I'm planning on redoing the tub for the spare tire in the back 
right corner of my t'all.  Anyone have ideas about how thick the 
steel is that I should look for?  I was going to pound the 
original steel out, then fit a 'tub' for the space.  I want to 
integrate the new tub with the old steel via steel rivets.  I'm 
not equipped to weld it in yet. I've got some hardward store 
galv. sheet steel, but it really is thin.  Am I looking for 16 
ga. 14 ga. 22 ga.?

     Thanks,


     -Joel Brodsky

         '76 IHC Scout II 345/tf727
         '75 IHC Travelall 150 4wd 392/tf727
         '72 Chev Carryall 3dr 4wd 350/th350 sold, but not forgotten.