Very cool drawing. I hope you found the 3D image of the Etec somewhere online. If you developed it yourself, you have WAY too much time on your hands
Since we're talking theory, here's another thing to think about. Boat balance at rest depends on the location of the CG relative to the center of buoyancy (CB). Once you're on plane, balance depends on CG location relative to the center of dynamic lift (CL). If you add buoyancy chambers, the added weight will move the CG slightly aft. The extra buoyancy will move the CB slightly aft. But they don't add running surface, so the CL stays the same. So you get the stern up in displacement mode, but you weigh it down when you're on plane.
Now this might not make enough difference to worry about. If you're adding 100 lbs of buoyancy and only 10 lbs of weight, it may be a good idea. But if you're adding 20 lbs. of weight to gain 50 lbs of buoyancy, it may not be worth the effort.
Dave