2. "reduce" air density by a factor of 1000.
This is easily doable. Climb to a height where air density is 1000 times less (about 60 km).
Lift should decrease 1000 times, except that Reynolds number also decreases 1000 times.
1. "reduce" air viscosity by a factor of... (pregnant pause.. + Dr. Evil cunning facial expression..) 1000.
You could achieve same result (increase of Reynolds number) by increasing the size of the airfoil, or by increasing density of air.
So, for a flat plate at an angle of attack, lower pressure on top, same higher pressure on the bottom.
No lift, just drag.
Why should the flat plate experience any forces at an angle to the plate in question? How could the flat plate experience any shear in absence of viscosity?