iti20090,
We have found that running 60D's on some tracks might be faster on the straight ,but the advantage is lost on the corners. The fastest laps are from cars fitted with small tyres due to the pushing/braking into corners of 60D fitted cars.
However at the end of the day the decision is yours.
Another person who can offer tyre and advice setup would be z-mann, however he doesn't post much these days.
Regards,
Calvin.