So the release edge shortens the back of the board, sort of like getting rid of the flip tip when it's at the back. Not necessary for normal twin tip riding but still maybe useable for wave riding.
I wonder if you could get rid of the step in just the center, so the step would only be next to the fin? Maybe point the flip tip some more.
What kind of foam do you use to shape a board like this?
It does make the board feel like it is only the length to the release edge when its at the back of the board, so there is less rear foot pressure than the overall length of the board would suggest. The Airush Hammer 144 by 42 for instance has 139cm between the release edges and the very curved rails mean that the board feels more like a 139 by 40 twintip.
The release edge's big advantage is that it glides much more cleanly over the water so there is less drag and the board planes earlier and goes faster. The sharp release edge seperates the water from the board much better, hence the greater efficiency.