Yes, rice bran and beet pulp can be used to balance each other out, but the way you are feeding rice bran and beet pulp isn't balanced. The ratio is 3 oz of rice bran to 1 pound of beet pulp (dry weight) to balance the ca:phos. And with an imbalance of ca:phos you often don't see really signs of problems even though they are there. One of the signs of calcium deficiency (which can be caused by too much phosphorus because it binds with the calcium and decreases absorption) is weight loss.
Since what you are really wanting is the fat content from both you would be better off feeding 1-2 cups of vegetable oil per day. And rather than a mix and match feeding program you would do better with just a ration balancer designed to be fed with good quality hay--it would help balance the whole diet's content of protien, vitamins and minerals in one product.
Licensed Veterinary Technician