Cut new battery/bellcrank mounting plate from .060 stock. Trimmed and finished outer edges and then clampted the old part to it to match drill the holes for mounting the plate on the tunnel and the bellcrank supports to the plate. Also marked and drilled corner holes for the bellcrank slot. Used a cutoff wheel to cut out the center slot and finished with files. Cut the channel pressed for me from .060 stock by another RV builder. Added the forward channel and drilled/clecoed into place, then used the battery to space the rear piece. After that was drilled/clecoed, I cut the side pieces to fit and used the battery to position them. Finally, I drilled the plates and fore/aft channels for the hold-down bolts 1/4" and drilled the hold-down channel to match, then trimmed the excess from the channel. New bolts will have to be 6.5" instead of 8". Next step will be to fabricate a solenoid bracket similar to the one on the original mount.
While I had the cutting wheel out, I marked the tail cone bottom skin for the cutouts for the air conditioning inlet and outlet. I drilled 1/4" corner holes and then used the cutoff wheel to cut away the rest of the hole. After much filing to finish the cutouts, the louvers were fitted into place along with their respective inlet boxes. Next I will countersink the louvers and dimple the skins, then have the louvers and battery mount parts powder coated.