Considering that my cat uses the toilet to drink from (despite our protests) I really doubt he would ever learn to use it for his litter box.
My girlfriend has the automatic box and seems to like it. I have one that might use it but there is no way my scardey cat would try it.
We've tried the silicone beads - nope
and several brands of clumping litter. They only like the brand we get at Costco.
I have one cat who likes to balance on the corner of the box (and tipping it over if there isn't enough litter to hold the thing down)
and we have one cat (the toilet drinker) who refuses to crouch so aims straight back - over the top of the box
so we tried a box with a cover and he would walk in and not turn around - just aimed out the door onto the floor
so we got one with a door and he aimed for the door and cleaned the door off on his fur as he came out
groan (hubby wants more cats - I never want to go through this again)
so now we have one of those 50 gallon bins and fill the bottom with enough litter that the acrobat can do his balnacing act on the corner without tipping it and the other one hits the walls with his rear-end aim before he jumps out.
I love them but their toilet behaviors are driving me crazy
and to be honest I doubt the would use two litters. The door one has been sitting in the basement for a year and neither will use it - not even one tiny pawprint