Richard.

Can I lower the front edge, i.e increase angle from horizontal for road use without much impact pls ?

Richard.

it seems there are 3 positions and its on the top one, moving to center ok for road ?

Richard.

All I can add is that the middle front setting of 3 looks SOOO MUUCH MORE NATURAL

GrantG

For road use, you may limit your rear vision, fuel economy, and top speed. Ideally, you are supposed to remove the block-off panels under the front of the car to balance the downforce across both axles (or the front could become light at speed).