Santiago, A passenger with a strut and yarn tell-tails might indicate the layers of unstable and stable air.

The further forward the wing, the less downforce on the rear axle, and the less lift in front.
The higher the wing, the drag lifts the front. Hard to predict the magnitude. Compromises.

The benefit of a windscreen might be realized without going full height. A low, wide forward deflector wrapped over on top might loft the airstream for some improvement. The air stays attached at or less than seven degrees.

We ran a Sorrell 50's vintage front engine (open) Can Am car. The pontoon fenders directed air at the driver and got under a full face helmet. Chin strap was almost decapitating at/over 100MPH. A small screen made it tolerable.
A winner-lap in a windshiedless Sunbeam Tiger broke my girlfriend's glasses when I shouted "Hold my flag and watch this schmidt".
jim