Since you and coosa are already friends
Cut the old wood out and top it off with 1/2 or 3/4 coosa. You already have a 2" ledge to lay it on and tab to the sides. 1708 on the top and bottom of the coosa and it's done forever. If you want to add strength to where the CC mounts, epoxy some 1x2 hard wood strips to the underside of the new coosa floor for the screws to go in to. Have fun!!