We’re having the same issue with Siena- lounging on her potty and dragging toys on there. We have a potty with grates, and the pooling on top that you mentioned hasn’t really been an issue. There area between holes is pretty thin so there’s not much surface area. I tried switching from pads to pellets the other day but realized pellets won’t work in this potty, which is a bummer. I’m currently changing pads and washing the potty daily but figure tgat won’t be forever. The hope is that eventually she’ll go outside most of the time, and the indoor potty will be there for times we’re not available to let her out.I also have a hard time sometimes telling if Mando has peed. He generally doesn't squat to pee or poop. I'll try the thinner layer of pellets. I might have to get a litter box with grates soon though. When he gets excited, he jumps around in his litter box and kicks pellets everywhere. I imagine that he might step on any pee that has pooled on top of the grates though. Then again, he sometimes accidentally gets pee on his paws now anyway.
He's also gotten a little too comfortable in his litter box and started laying down in it for some reason....but that's a whole other ball of wax that we're trying to address right now.