Tetrastar C or RTK

I’m going to be purchasing an Agleader in command 1200 7500 receiver and steady steer for my planting/side dressing tractor and sprayer, and possibly combine my question is should I spend the extra money on RTK being that we just locally got a tower put up? Or should I settle for terrastar C? I will be planting, side dressing, and spraying with the steady steer.