I've never seen a gear like this one before, and it's an interesting idea. The down side to using it is that, whether I was splitting a 4 ply into (2) x 2 ply yarns, a 6 ply into (3) x 2 ply yarns, or an 8 ply into (4) x 2 ply yarns, the yarns would always occupy the same real estate on the drum. I'd want to spread the yarns over almost all of the drum however many new plies the splitter makes. So, if I were making (2) x 2 ply yarns, each of the 2 plies would be distributed over almost half of the drum, and so on.
I'm happy to keep posting here; it's a friendly, well informed place. But as I lean away from using any Arduino hardware, or software, I'm wondering if I might be veering off topic too much? I'm guessing that there must be a forum that's better suited for amateur mechanical engineering topics such as this one is becoming.