Sorry for my late reply, I totally missed your message.
Yeah, who would've thought that good, strong magnets can be so expensive. It indeed makes it an expensive DIY project, especially if there's a lot of trial and error.
I do agree with your view from the customer's perspective. We like the walnut wood for its nice patterns and availability, but it is indeed not as exotic as some more rare woods. We switched already the handles on the ZDP-189 Bunka Black from a nicer looking rosewood because this wood is getting on the brink of extinction, so we didnt want to contribute to that anymore. We'll discuss it internally to investigate other options for the wood selection of magnetic holders.
Magnets are strong enough to support cleavers too. We'd recommend putting the cleaver on the far right (or left side) and then it shouldn't be a problem space-wise, it won't block the second magnet. Unless you have a really supersized cleaver :)