"entry-level hobbyist/prototype" : give a big cooking pot a try first. Switch it on, wait, switch it off at 230C.
I am going to do this!
I thought you were being flippant at first but then I found this epic thread:
https://www.imdes.de/produkt/mini-condens-it/?lang=enwhich referenced this demo:
and showed the basic technique for desoldering with vapor too:
and now this all makes total sense to me. You heat the Galden liquid, at 230C it becomes a heavy vapour that rises up a little bit to cover the board, it cools and falls before it escapes from the pot, and the vapor that condenses onto the PCB will be at exactly 230C to bring everything to the right temperature without overheating.
Just be careful not to heat it above 300C or it will turn into acid and kill you :-)
I'm sold! Just trying to work out where to buy a suitable pyrex beaker or asparagus pot in my neck of the woods...