I have two Line 6 Spider IV 75 amps. I would like to use them as a pair one stage left, one stage right, both being controlled by the same floorboard. I am currently running a guitar cable rather than a wireless rig (thanks FCC). I own an FBV Sohrtboard MkII, FBV Shortboard Mk1, FBV Express MkII, and FBV ExpressMk1 so whichever one would be the better option. What would be the best way to do this?