Tramlining - ways to help?

[RoadRacer]

I'm only 100 road miles into my car, and just had it aligned to the specs below, based on the manual suggestions.

alignment.jpg 2021-03-01 13.30.50.jpg alignment1.jpg

Before alignment, it was hardish to turn while parking, given my 285/30 front tires I wasn't surprised. I could have coped with it, but after alignment the car is pretty light steering, and much easier at parking speeds. BUT it's also very light when driving, darting all over the place to the point that it seems unsafe to drive quickly.

Looking up "online" many call this tramlining, but I'm not convinced that's the right description. It may be caused by a grooved road surface, but to me it was also happening on smooth roads. I'd describe it more like being blown sideways by the wind, or a passing semi. Very twitchy.

Since I couldn't find a thread here on this subject, here we are.

First I'm going to try lowering tire pressures and see if that helps at all. I haven't checked what the alignment shop put in yet, probably 35-40lbs in there. Then I was wondering about how I could play with caster or toe, to see what helped. Camber wouldn't be involved in my mind.

Anyone played with this? Suggestions?