Would love to see your set up. As Jim mentioned, it is easier to carry the left front on a high banked track. Normally, that is not the problems that I get requests for. Most of the Bando requests are for relatively flat tracks or tracks that make an abrubt change from flat to banked.
Yes, stiffen the right rear sping to help plant the left front wheel.
Yes, it would be less friction. But, is he able to control the car with the left front wheel in the air. If yes, and he is fast; then I wouldn't worry about it too much.
Steve