It was clear to me that you were using a 2x3 (or 2 2x3's), Dan.
I shoot 6x7, 6x9 and 6x12 rollfilm with my 8x10 Wehman. I have a 4x5 Graflock reducing back for the Wehman and several rollfilm backs.
The Wehman may be about the same weight as your tandem graphic??