So yes, it's been a while, but at long last I've been making progress. The thing with pylons is, they're big. If you want to take them with you, you pretty much have to go flat-packed. Like so:
On the pylon side, I drilled 3 roughly equidistant holes, glued the magnets in, waited for everything to dry, and then added a spot of paint on top of the magnets. I pressed the other part while the paint was wet, which gave me the place to drill…
… I then drilled where the paint was, put on more magnets (taking care I got the polarity right), and here we are:
While I was at it, I assembled the centre of the pylon: glued the 3 parts together, then added 1mm brass rod in 4 places. The rod is not flush, the idea is to fill the hole with a bit of green stuff. It was quick to do, and ensures the thing will not break apart. The joint in the middle will be filled with green stuff as well - easier than spending time trying to get the two parts fit exactly.