By the numbers, Ben is Stage 2 bordering Stage 3.
With a phosphorus of 6, you need to start binders. Your goal is to get the phosphorus under 6 if possible. The dosage is 14-28 mg per lb per day. (1/4 tsp of ALOH powder is approx. 300 mg). As an example, say Ben is 10 lbs so the dosage for the whole day would be 280 mg. So you would add 1/8 tsp to two meals ( a smidge extra is ok as it would be nearly impossible to get exactly 280 mg). The binder needs to be in the food as it is consumed or orally dosed after eating. I would use the higher dose of 28 mg per lb until you get the level below 6. You can get ALOH from a variety of sources, this from Tanya's site:
Thriving Pets in the USA sells 500g (1.1 lbs) of aluminium hydroxide dry gel for US$79.95 plus shipping. They also sell 1 oz at a time, as well as capsule or liquid (oral) formulations (these require a prescription, which the gel formulation does not) . If you enter the word "tanya" (without the ") in the promotional code box, you will receive a 10% discount on orders over US$55. Shipping is free for orders over US$55 after the discount.
I know a pound seems like a lot, but it will last for a long time.
Keep an eye on the potassium, it is fine now but can drop. Watch the calcium also it is getting on the high end of the scale. If it goes higher the first thing to try is changing food.
Anemia is another issue to be on the look out for. Ben's RBC is good but you can start now to add B12 and B Complex once a day into his food. B12 is 500mg and B Complex is 1/10th of a capsule. Given that Ben is also diabetic just like Squeaker you need to look for products without sugar. I use Solgar Brand from a local health food store. Make sure to get the B12 that is just cobalamin rather than the cyanocobalamin. Do not use the Yarrow B despite the fact it is the preferred methylcobalamin---------it contains sugar.
I also give Squeaker 1.25 mg of Omega 3 twice a day. I use the Nordic Naturals Omega 3 Pet formula. Again I get this at my local health food store.
I would also suggest that you begin to familiarize yourself with the process of giving sub-q fluids and begin to monitor Ben for dehydration----pull up the skin on the back if his neck and see how quickly it falls back into place and/or roll the skin between your fingers. If it goes back into place quickly hydration is adequate; on the other hand if the skin sticks together then he is dehydrated. You can also feel his gums if they feel tacky that indicates dehydration. You can find wonderful how videos on you tube.
I know that Tanya's website is overwhelming in the volume of information, start digesting it in little bits now. One of the many areas that will benefit you right now is the nausea and stomach acid information. This way you can monitor and be ready when the issue occurs.