Decided to mount the Main and Engine busses on the F-728A Bellcrank Channel. Some time was spent finding the best location so the mounting bolts/nuts would not interfere with the Elevator Bellcrank through it's entire range. After drilling the mounting and keeper rivet holes in the doubler, I then used the doubler as a template for drilling the holes in the F-728A Bellcrank Channel. Next, I installed the doublers, then secured the busses with 3/16 diameter pan-head bolts and nylock nuts on the back-side. Nice and secure, close to the contactors and does not interfere with the Elevator Bellcrank movement.
Doublers used a templates to drill holes in F-728A
Doublers installed with keeper rivets
Busses securely mounted (Note: the buss on top required a little plastic removed to clear two rivets)