OK, a bit of a summary here.
1. Cutting magnets sounds difficult and like it would need some specialized tooling. Not worth it to me, I'll buy the precut ALNICOs first.
2. It also sounds dangerous - I have certainly heard stories about bloodied, flattened skin when it comes to the really strong ones. Didn't really think about them shattering in more or less an explosion if they got too close - thanks for that heads up, @gunrunnerjohn !!
3. Thanks to @stan2004 for the heads up on the JB Weld and neodymiums. Again knew about it, just didn't even think about the magnetic pulling on the steel pieces!
4. Thanks to @Norton for your thoughts - I was also worried about the neodymiums being potentially too strong!
5. Thanks to everyone else for your thought and for chippin' in!
6. I also learned what a PIA dehumififers can be - 'course I already knew that, been running one (or more) in my basement in rainy Ohio for a lotta years. Don't need 'em now that I'm living on a slab in southeast Tennessee!