It will get better, Nancy

Bhooma
@Bandit's Mom had to hold my spirit up for the first few months when I saw Fistuk loosing his mobility, needed to be carried to the toilet, sometimes held in the toilet boy so he doesn't fall over and wet himself completely, and get his butt and hind legs cleaned from pee or poo. It does get better! I know it's heartbreaking to witness.
As
@Heather82372 said, each cat has its sweet spot. For Fistuk it was 5.5U when his body suddenly took a sharp turn.
ECID. Notice more of what Bailie needs and learn his patterns. It'll become more easy to notice the patterns and know what he needs and how to best support him.
As
@Karolina KJ & Nestle said, perhaps you can also consider the litter you're using and what would support him best.
I tried different kinds and eventually found the wooden whole pallets (not chips) filled to a certain level hold him best and he doesn't lose his balance more pee on himself.
I was advised to cut the front go the toilet box to make it easier for him to step and after few trials with different boxes I noticed that he prefers to climb into the bigger one with the higher rim. I guess it has something to do with feeling he can have some privacy in the toilet. So I give him what he prefers. You can try different boxes to see which one he prefers.
It's a lot of trial and error but I'm confident you'll find what works best for Bailie

