Mixing own horsefeed

Does anyone have a formula they have used with success
When having their own horse feed mixed?

I was thinking of ordering a
30% whole oats
20% beet pulp
30% alfalfa pellets
10% rice bran
10% barley OR Soy meal
Mix with a 1% salt per ton

Suggestions? Too much in oats?

We feed Triple Crown Complete now. Those ingredient up there are the top ing. In that mix, but we pay $18 a 50 verses mixing it would run about $24 a 100.
I looked over everything and ended up with:
35% Whole Oats
15% Rice Bran
40% Alfalfa Pellets
5% Soy Bean Meal
And a 1% Horse Mineral/Salt mixed in
I have a few weeks so call back and change the
Mix because they have rice bran on order and
It is going to take nearly 2 weeks to get it,
So if anyone has suggestions, please comment.

We have 1 Arab Stallion, 1 Arab broodmare, 1 Arab 2 yr filly and a pony who gets a handful of anything like the above, at most, a day plus his hay.
They get minimal exercise in this weather.