After watching LB's video several times we went with no front fenders but front trailing fenders and rear fenders. The body was already shaped such that drilling the front holes further back was difficult.
What if we took a piece of 1/64" plywood and layed it on edge along the body so it covered the backside of the front wheel? We could bend it around the front of the wheel, cut and taper it somehow. This way it would be mounted solidly to the body and keep air from getting into the back of the wheel. This would, however, direct air over the top of the car rather around the outside of the wheels.
Would a piece of plywood work also as an extension to the inside of rear fenders? It would attach to the inside of the rear fender and stand on edge along the backside of the rear wheel. This would prevent air from getting into the backsided of the rear wheel.