A cat usually turns round so that it can see who is watching it,
You can determine the height by the amount of litter. If you have a lot of litter it is 13cm, if you have little litter it is 18cm.
You can make the entrance even higher with a cardboard box (with stiff insulating tape). She might like it even more hidden anyway.
Otherwise stick a large transparent cloth (veil) over the whole thing. Very wide and 5cm above the floor of the room. The cat will find its way through once it knows it.

Hello, the ball is designed for large cats. I personally have 2 large Ragdolls and it's the most spacious I've found.
It also makes it easier for the cat to turn around. The measurements already given seem accurate (it all depends on how full the litter box is). I've got the footboard at the front, which also allows the cat to get in without jumping out, and to be in front of it (perhaps it's also safer for the cat to get a good position inside).

Hello, my cat had the same problem... I don't know the dimensions because I had to sell the appliance again.
But yes, the edge is slightly higher than on other devices, but if the cat doesn't turn round after getting in, its bum stays 'outside' and it misses 🙈 (if it doesn't sit down)

The litter tray is designed for domestic cats and not for jungle tigers.