If someone wants a challenge here's something to dig into.

Changes / findings:
Probably negative toe is the way to go, but I feel its too unpredictable and while the fast lap is in there - it's rarely going to actually materialize.

Car is pretty unresponsive aerodynamically, so for a race just increase rear ride height to counter the front fuel load.

The slower race time is done with positive toe. It makes the car much more stable, you can push into the corners on the brake more aggressively without losing the rear right away. However, mid turn rotation is quite noticably reduced and you need to wait longer to floor the throttle. Yet, much easier to drive and more predictable in the end. Maybe the dropoff with the positive toe isn't making the car as nervous as with negative toe and over a longer run has more benefits.

It seems to be a matter of preference and driver skill. If you are already fairly good in feeling when the rear end steps out, then go for negative toe. If you are not yet on the peak of your powers and you rather want to finish the race while others spin off, use the positive toe variant. Also play around with the lower positive toe range from 0.0 to 0.1 - I would not higher as it really kills any corner speed. Maybe this can be addressed with a higher rear ride height, but I doubt thats overall beneficial.

For testing purposes the race laps are done with 100l - you will hardly need that much for 1h races. 

Best of luck :)

*in the replay check the time table to find the correct lap