1. No vent hole to prevent pressure build-up (pretty serious problem).
-> there is one: the exit hole. There is no liquid alcohol that remains in it
2. Top heavy, with all that condenser water.
-> well the measures aren't like in the pictures... 2mm between two copper parts is enough. Sure quite heavy, but not that much.
3. How do you switch on water flow into the centre section to induce reflux?
-> you don't. The water in grey is simply poured before the beginning, and all the alcohol that gets cool is removed.
4. Practically it is looks a pain to build.
-> obviously, yes
