[McGillicuddy]

One thing to consider is the motor height is usually raised one inch per foot of set back. Bay Manufacturing makes 5 inch shaft extension kits for many motors and might be a good route to go with your waterproof Yammie if thats what you'll be mounting on the bracket. They run 500-600 clams and some guys have found them much cheaper on ebay and such. I think if you're going custom to stick with your 20" shaft, you simply chop the flotation chamber rather than moving the bracket down. The latter effectively increases drag. Keep in mind that as you move the motor aft you cg will also move aft and your motor will sit even lower in the water, at least while at rest.