I have had good luck with my babies, they are a little over 2 months old now, and since there are so many in there (7) I have to clean their litter box every day, if I do not clean it, they will empty their food dish and use that instead. My secret was paper towel! I lined their cage with cheap paper towel, and then the poop was easy to spot, I would just put it in the litter box, which had some ripped paper towels in it, just so it was not empty, and then when they peed out side of the litter box I was able to spot that as well right away and would rip off the wet part and place it in the litter box as well. And as for the tipping litter box, mine has a small hole between the hooks, so I use a twist tie to tie it to the bars.
Some of the adults used to be litter trained, but once they moved into the RUUD and in with other adults that are not litter trained, they don't always bother, so I will have to work with them again, once I can figure that out.