double magnetic coupling

This is a modified modification of my original couplings for ho/oo model railways. https://www.thingiverse.com/thing:5621727.
Glue 3mm by 1mm rare earth magnets on the ends of the prongs. The magnets should be of opposite polarity and should always be attached in the same way on every coupling.That is, for example, always south on the long prong and north on the short one
In theory (I think) the bond will be twice as strong and the coupling will be "universal" - that is, any wagon/carriage can be attached at either end to another one.
I found it useful to take a rod of joined magnets and mark one end with a permanent marker. Put it aside and mark the next one and so on. That way, you can easily see which way round the magnets need to be attached to the prongs.