I think you guys have it a little wrong. The blackhawk drive has a very short vertical distance between the input and the prop shaft. It also is a surface drive that is designed to run with the bullet only slightly submerged when on plane. The transom cutout for the blackhawk drive is LOWER than the bravo cutout.
Also the blackhawk drive creates tremendous transom lift and almost no bow lift so the boat has to be built with a lot of natural bow lift and a rocker in the bottom. If you remove the blackhawk drives I feel you will not be happy with not only the performance but the handling. The bravo drives will be so low in the water that triming the drives may not help much.