First of all OI, congratulations, for getting the virgin voyage in and only having one piddly little complaint. Well done.
Second, I think the coolness of your front wheels could be exaggerating the affect of the large caster angle. I really like your old style, all matching wheels, but the front ones look like they have a nice dish to them. An imaginary line down through the middle of your front tires should intersect the imaginary line through your kingpin, at dirt level, and I think yours will cross below ground a few inches. I think this will make each tire want to pull to the outside.
If lessening the toe in doesn't work, try making it more. Could you lessen your caster?
Good luck.