Food Help for Cat with Struvite and Calcium Oxalate

My cat is a 7 yr old DSH male who was diagnosed with Struvite AND calcium Oxalate crystals in his urine around 7 months ago. He had a blockage but it resolved without surgery.

He was on Fromm (grain-free) before the crystals. We switched to Hills C/D per the vet, but had a relapse of accidents so we switched him to C/D Stress a few months ago and have been accident-free.

My other cat is 6 and was just diagnosed with epilepsy and I read that it is better for him to be on a grain-free food. I am very unimpressed with the ingredients in the Hills food.

I am very interested in a homemade, maybe raw diet for them, but I am worried about my crystal urine cat having issues without his prescription. I have found info on one type of crystal or the other but since he had both it seems more complicated! I would prefer to feed them the same food since they end up sharing anyways and I can't always supervise.

Any thoughts? And thank you in advance!!

Are you feeding wet RX food or dry, or both? I've never had a cat with urinary issues, but If i did I would have them on a 100% wet, raw, or homemade diet. Ideally you want to make these changes in your cats diet under the supervision of a vet that supports moving away from RX foods, so you might want to start searching for a different vet. A lot of holistic based vets tend to support bio appropriate diets better than mainstream vets. 

Here's some info that might be helpful. Good luck. 

http://www.catinfo.org/?link=urinarytracthealth