Not to hijack your post, but I'm having the same issues.

To clarify some posts on Facebook, I have 5 litter boxes for 5 cats. Three are humongous litter boxes and two are large. There is a 6th small one in the kitchen for accidents. Added recently due to these issues.

I prefer the wheat-corn litters and apparently so do my kitties. However, I have recently been diagnosed with Celiac disease and the wheat has to go. If it touches my skin, I break out in hives.

This has prompted some protest pees and poops. I'm at my limit.

Good luck with your search for a solution. Mine might have to be drastic.