mock it up on blocks where you want it to "float" look at it from the side and cut a few peices that match the open space under the amp. get some 14-16gauge plate and cut to mount to the feet, but not be seen, and extend under the amp. mount the blocks to the rack, and the plate, and then mount the amp to the plate. you are gonna want to dynamat, or camper tape the plate where the amp sits on it, or it will buzz. top it of with some nice hex socket head "screws" to mount with.