In order to magnetize devastators you have to magnetize arms as well as the different back packs. If you don't have a rotary tool like a dremel, invest into a hobby knife or a pin vise with a chuck that can hold a 3/16 drill bit. It's the entry investment into magnetizing but 3/16 is the standard sized magnets used in infantry as well as small weapon mounts on vehicles. Now when going about the process you could take the easy way out, but the more financially practical way would be to utilize a metal seat for each magnet to stick on. Only thing off the top of my head right now would be something like a 3/16 machine screw. screws are a lot cheaper per package than magnets but it'll take a bit of out of the box thinking to make em work the way you want.