No idea about Catz, but I breed PB/NIB spotless Dalmatians in Petz 4, so I'm happy to answer whatever questions you have about them. (Disclaimer: This is just my personal experience.)
You're saying you're breeding Dalmatians who exhibit few(er) spots, but you can't get a spotless one. Your goal should be to work your way toward breeding a pair of
parents whose offspring frequently exhibits 1-5 spots, ideally trying for as few spots as possible. With a good pair of breeding parents like these, there's a high chance they will eventually produce spotless offspring, especially if they produce 1-spot Dalmatians regularly.
The confusion when breeding Dalmatians stems from the fact that there's so many factors at play, including the mother's genetics, the father's genetics, the offspring's mutations (if any), and sometimes a combination of all three. To make matters worse, how a pet looks is not always indicative of the genes they carry. You can have a desirable-looking pet who carries undesirable genes and never produces the kind of offspring you're aiming for.
And you can have an undesirable-looking pet who carries desirable genes and consistently produces desirable-looking offspring, but usually you'll judge the pet by its appearance and accidentally delete it. In the end, it really doesn't matter what the parents
look like so long as they're consistently producing desirable-looking offspring (aka the parents are carrying ideal genes). How their offspring looks is key, and without using third-party tools, it's the most reliable way to reveal the
parents' genetics. And for me, my goal is not just to breed ideal offspring, but to breed ideal
parents. It's all about the parents, if that makes sense.
All that said, if you like tools, check out
GenePoolz. But if you have any specific questions, let me know.
Spotless Dalis from my line. n_n