between
I've been doing the same thing with my too numerous test leads but using more than a dozen hard disk drive magnets, which seem to be a lot stronger than magnetron magnets. They're abitch to get off the fridge, tho. So far I've held up to the overhead (modular cabinet) over a quarter inch of 8.5 x 11 paper sheets with those magnets, and they are so strong that a single sheet might get munched if I'm not careful when removing it.
There seem to be a _lot_ more defunct (or just obsolete) hard disks than there are magnetrons. By obsolete I mean less than about ten gigs.