Sometimes it is best to leave the numbers grey.

Put out scouts about 1-3 Km in front of the Vanguard/Main Body. Put scouts out on the flanks as well. About 10  horses in each detachment. If they detect anything, they do not stand and fight, they return to you and tell you what they find. This way, you do not get surprised. Leave a small detachment in the rear to act as a rear guard. Maybe the remainder of the horse. Use your squires, son and other knights in your party as runners to pass information back and forth while coordinating a fight.