Except for bottom bulb, and just react to that footbraking?
As I am gonna get chased most all the time, and go red my fair share, wondering if adjusting myself to just seeing the bottom bulb with rest of tree blocked out might help?

Won't let you at a big track, might get away with it at a smaller one, won't even let you tape your helmet shield.

Some of the biggest footbrake races in the States are allowing this now. Years ago it said no blinders in the rulebook but I don't know if its still in there.

I've seen many guys hold up index cards to block parts of the tree.

It is legal to mount one to the sunvisor, at least at tracks out west, don't think the tape on the windshield is, Ive seen people get by with the helmet shield, but that probably depends on the track.

I've done that before with great results. When it got dark, that goes down the toilet as you'll see the glare from the 2nd bulb under your binder. That might throw you off. Give it a shot. I've been top bulb racing for years now and if I had to go back, I'd suck.