Alembic head design considerations?

[Steve Broady]

If the answer to my question is out there, I am too dumb to find it, or I gave up too soon. I’m looking for any information about the factors that go into designing an alembic dome, onion head, or anything similar. Volume, surface area, vapor speed, cross section, anything. All I’ve been able to find are pictures, some comments about how much of a difference they’ve made , some saying they’re old fashioned and not useful, and plenty of companies selling them. What I can’t find is any information on designing and building my own. Can anyone help, please? I’m not asking anyone to do my homework for me. I’m trying to do it myself. I just need a hint on how to get started.