Yeah 3box and boost 2 toons with your shammy to get the RAF bonus is probably the best way. If you don't mind a little extra work, you can start up a DK.. level him to 70 (shouldn't take more than a week) then buy the cobalt defense set and use him to boost. Add's to survivability and allows larger pulls.

You're 80 will do just fine, I just prefer an actual tank for boosting. Dk's can be leveled up extremely fast. Their starter gear will last them well into Nagrand so you can sell their stuff for extra gold.