I think the answer is pretty obvious in this case - the US uses feet and inches, so 32" is just a round number.
My 5 string has 35" scale, because the designer thought it was better than 34", for the low B. There are 5 strings with 34", 32" and so on, and they all work. I wouldn't get hung up on the perfect design, there isn't one. And from everything I have read on this forum, the first bass you make won't be the last, it's the one you learn on.
So if 32" feels about right to you, and everyone with experience says Newtone will make strings to sound good, then go with that length, and move on to the next decision.
(Disclaimer: my first bass build is postponed until retirement, and also when I feel I can play the damn' thing well enough!)