Wouldn't think that 2F becomes very unstable with wing at low drag position you still can drive fast in straight and gentle turns, but you certainly have to be driving the car with way greater care to stay in control, usually simply must go slower through some places. It is very interesting car indeed. One interesting thing about front flap is that it opened automatically at about 190km/h and chanelled air under the car, which is really strange, this means that at low drag setting front developed too much downforce which unbalanced the car, I can't think of other explanation. Perhaps they used it only for Le mans ? I also guess that they would disable front flap for some tracks, I don't think any other track made sense for front flap. Rear wing must also have been equally important as air brake system. In one source it says that wing at high attack angle lowered top speed by 15mp/h, other source gives much larger figure. Anyway if it was something between 25-to-40khm/h of drag for the wing that is as tall as skyscraper its resultant drag force location must have been quite high. This means that aerodynamic drag would result in backwards pitching moment of force. This I can also believe not being ideal in some cases, there must have been proper front downforce to counter balance that. Right now I have pretty optymistic settings, I still couldn't do 3'35'600 laptime at spa, best so far was 3'40, could ISI SPA 1966 be slightly too slow for some reason ? Of course I may not be Phil Hill, though I don't think he was attempting suicide that day, even more so as his closest rival in qualification was Mirage M1 GT40 (probably driven by Ickx) that did 3'39'0.