70% on NG's for Severe Icing conditions which I think is the same for Classics.
Static t/o's can increase your brake temp with t/o power set. Possibly meaning any failure before v1 and you abandon the t/o roll could lead to you not having the braking capacity to stop.
That is what I have been told anyway. I personally would use static if you have to back track and do a 180. If no back track a rolling. Not my SOP's though.