Peggy Sue's advice is solid. I would go with what she recommends.
If you don't want to feed one of the higher protein ration balancers, then don't feed any grain at all. 3.5 lbs of the feed you want to give is NOT enough for full nutrition, so just don't bother.
I feed alfalfa pellets or chopped alfalfa hay (3 lbs), whole oats (1 lb), and a vitamin supplement designed for horses on little to no fortified grain. Right now I'm using Smart Pak's Smart Vite Maintenence Grass: http://www.smartpakequine.com/produc...ctClassid=4579
I would feed the above, plus add either whole flax seeds (2 cups) or corn oil (working up to 1 cup) or stabilized rice bran (working up to 2 lbs).
The above would give you full nutrition plus high levels of fat. Get your horses' teeth done and be sure they are dewormed properly. If you haven't dewormed them in the past 2 months, or you used something ineffective last time, then deworm now with Ivermectin and Quest Plus in 6 weeks. That will clear out all the parasites so they will better utilize the feed they eat.