i think if you use a all round mix( which had peas/beans in it ) with 25% barley added is not a bad mix then add 25% maize to this from tuesday or wednesday,
but after 250 miles i would drop the barley and add more maize and fats to the breeding mix maybe
50% breeding , 40% maize 10% fats you can get any energy type mix for 250 miles plus
up to 200 miles fed all they want on saturday of barley /protein/seed mix .then only around 1 oz sunday and monday, tuesday 1 and1/4 ,wed 1 1/2 ,thursday all they want , friday just energy mix all they want
over 200 you will need to feed more early in the week