>>7543865There are a variety of manufacturers, I don't remember who made mine, I picked them up at an LGS. They're known as rare earth magnets or neodymium.
>>7543867Yes they will. The tiniest probably won't hold that boomerang particularly well, but I'd bet 3 or 4mm would. The only downside is the piece will rotate if you don't have some manner of catch to prevent it from doing so.
>>7543871Other options include scratchbuilding a bigger centrepiece that holds it like the MG.
