outboard power on larger cruising cats

We are expecting to spend $10-12K for the engines, control box and cables and will try to recoup some of that through selling the inboard parts, the boat has 1 brand new Kubota v1505 diesel, 1 rebuilt same and 1 new saildrive leg. The engines are non marinized industrial units. we are hoping that the existing control box will be usable for the outboards but probably not. We have come up with what we feel will be a workable design for the motor mounts that will hinge down from a point below the bulkhead where you enter the cabin from the cockpit, there is a 5" step under the bridgedeck at that point so the brackets will be about 6ft long which places the motors just behind the aft beam which is realistically as far forward that we can expect. Anyway we will be drawing it up full size on a sheet of plywood to work out the geometry and then fabricating them out of aluminum. our next trip to the boat will be over xmas for 3 weeks and we need to install everything then.

Steve.