Personally I vote for 1mm thinner! Although, I'm not sure if having bare magnets on the backside will attract random metal objects nearby. Every once in a while you'd have to brush staple pins and paperclips off your pocket Possibly a stupid idea: https://dl.dropboxusercontent.com/u/1219940/n2c1zo.jpg Use some crazy glue to hold the magnet in place. This way the magnet is closer to the other-other half and the wood covers the whole back side (thus distancing magnets from attracting paperclips).