You have to trust your reinforcements. Attack so that you have three armies against to of them. Use all cavalry armies (1 gen, 5 - 6 Quapukulu and the rest HAs). You can use old generals as extra heavy cavalry. Let them die in a blaze of glory. I used this strategy and focused on the battlefield on the Mongol generals. They have to die! Using four stacks of my own with fresh troops and inexperienced generals I defeated 4 and a 1/2 Mongol stacks (see my sig) in a couple of battles. I lost only one battle. Have fun and enjoy the view of a screen full of galloping, charging cavalry.