40-41 ford pickup chassis help

I'm working on a 40 ford pickup. I have some rust through on the frame rails that needs repair. Wondering what gauge steel I need? It looks to be 12 gauge but I want to be sure. Also...is regular galvanized the way to go? Thanks for any help.

 

10 gauge pickups, 11 gauge cars I believe. Read it in some book.
Hold the galvanized, reg mild steel.

 

35-40 frame patch panels:

http://www.precisioncoachworks.com/

 

Thanks for the help! It's much appreciated.

 

Don't use galvanized metal. HRP

 

X2 on precision they fit well.