coltonandrew -- I'm curious about the 3/4" conduit frame and plywood box. Will it have any function other than wake filling?
The reason I ask is those materials could make an efficient shape or a vortex-inducing nightmare. There is a lot of opportunity in this, most of people are hamstrung when they can't let go of the un-tapered bed.
Those 4"s you mention should be dealt with. How far along are you with that?
This is what you should emulate:
