[Number 3]

First, without using CFD to at least provide some data, it’s tough to just throw numbers around like this based on Corvette. You’d be surprised at the little things that can impact aerodynamics. As pointed out, the base aero of the cars body and shape has so much impact on how the air will hit that wing and what it can actually do. Speaking from experience here.

Second any wing that provides more down force also provides less FE.

Third, OP I appreciate the effort here. A ton of work. But the wing is overpowering the appearance of the car. 7” wider is simply too big for the appearance, just JMO and that’s something others might appreciate. Good luck.