Yes, I would recommend removing the backplate, and the one-way bearing as well. Kellum Machine Works make a pullstart replacement backplate for the K4.6, that should work fine. There really wouldn't be a durability issue with leaving the pullstart on the engine, but it will rob power and cause vacuum leaks.

As for the starter box, pick up the Ofna chrome-top, part number 10250. Position the front of the truck towards the hinge and set it up from there.