Looks good!
I will be fabing up my Dual trans Coolers tomorrow. I am using 2-18" Tubular style coolers, the ones with the fins on them and have the inlet and outlet on the same side. They will be mounted behind the rear axle like yours. My spare tire well is still intact. I am hoping that mounting them back there away from the heat of the radiator and engine will help keep the trans cool. I do not have anymore room up front for anything else except a tubular/canister style radiator overflow tank.