You don't. Sharingan allows you to read movements a lot easier than one is normally capable of which is why he managed to copy the movements of one of the testers during the 1st portion of the Chuunin Exams. No Precognition was present or he would've began writing his answers earlier than the person he was copying as to better conceal his attempts at cheating.
But provide scans that the 1 or 2 Tomoe Sharingan can predict movements and I'll concede because I can assure you, there is no such thing.