Here is how I braced my cab. It worked good. If you get alot of bracing then it limits your movement while working on it.
I wish I had removed my rockers prior to sandblasting. This is what I had to deal with. Most of that metal was replced. There was still rust in the corners that I had to clean up and treat. I could have saved alot of time and frustration.
So, I would brace it, remove outer rockers and get it blasted and then etch prime everything. Just my.02