MM, there's no reason to put the lens on a recessed board if you want to try it on a 4x5 Speed Graphic. I don't know which 4x5 Speed you have. The two most likely are Anniversary and Pacemaker, minimum extensions 65.1 and 66.7 mm respectively. They should easily focus a 4" triplet on a flat board to infinity.
There's no reason not to use a Graphic with the front standard inside the box. How do you think we use short lenses on them?
As Dave told you, a 103 Graftar won't cover 4x5. I don't know how large a circle it illuminates, so I don't know whether it will give you negs with exposed centers and completely unexposed corners.