You would only need Higgins and Mazuri,no need to keep the Oxbow as a part of the diet as all it would add is fiber which really isn't important since the two foods combined give enough fiber.
As for amounts of each food,the ratio to get 18% protein,6.78% fat,and 7.28% fiber is just a 60% Higgins Sunburst and 40% Mazuri Rat and Mouse ratio.Sounds overly complicated,but really it isn't!Invest in a kitchen scale anyways,they're extremely useful to keep weight checked on and can alert you right away to sudden weight loss or gain which could impact health.You'd just need to measure out 6 grams or 7.2 grams of Higgins and 4 or 4.8 grams of Mazuri,depending on the total you want(10 grams or 12 grams).You could do this every few weeks and set portions of food in containers and keep it in a cool dry place and this would mean not having to prepare the food every single day
