I can see where that would be a issue on your car. Because of your excellent aero cd you have very little aero-drag to overcome. So there would be a very fine line between engine braking and engine power. So the smallest change in the road from flat to a very,very small decline would cause engine braking.
The only thing I can think that would work without in depth building something would be a management system with the fuel table displayed at dash level or even above the dash.
Here's a example off my car going a dip in the road.
Fuel table - YouTube