I printed these in PLA, without support. I used 4 layers for the top, bottom and 4 perimeters (or more if needed) to ensure the strength of the stopper. I also added 30-50% infill to get a nice and sturdy part. The stand can be easily placed on top of the soldering iron body, so there are holes for the magnet at the bottom. The size of the magnet I use is (D16xH2) mm. Supported solder size "Senju Metal Solder M705 0.6" I think other sizes are also suitable.