Bearing in mind I am printing in PLA, I am using any old super glue for the chin pieces.
For the rest of the helmet, although I intend to glue one up and try painting one, presently, the tension pins hold it together well enough for effect. It is the intent to fully glue, just its a one way operation. I have enough instances now I can experiment, just time ( read lazy )
Super glue will hold the magnets and cups in, "mostly", as they are very shiny, they can break the bond, I need to rough up a couple on the back side and see if it helps.
I also have some "proper" PLA glue sitting in the drawer, but again have not had time to experiment.