I read your thread the other day. I knew I wanted to reply, but I had to wait when I had more time and my frame of mind was in a better place so I could give you a more intelligent reply.
I have never been to a HBS that had EVERYTHING I wanted when I was there (even a particular strain of yeast that I just HAD TO HAVE TODAY because of a planned brewing session), and I don't expect you to either.
At my house I have a better selection of yeast, more air locks, bungs, primary buckets, and books than some HBS I've been in.
There is no way you will ever have everything that everyone of us want. That's totally understood.
I have worked within the Army's retail and wholesale supply system for over 30 years so I know how supply pipelines work. I am also a college graduate so I know some general business (enough to know that I have no interest in running one, but I can maintain an intelligent conversation on the subject). It's just bad business (and common sense) to tie up your inventory dollars up for an obscure item that you sell one of in 3 years. That's a "special order", 2-4 weeks waiting time. It's all the little stuff that's going to blow you out of the water.
Other than a passion and desire to own a HBS be sure you take some business classes.
Nowadays, I just lower my expectations and don't get my hope up whenever I walk into a HBS. This way, if I come out with something I wanted I prefer to be pleasant for the rest of the day.
Other than that I do mail order.
In all sincerity, good luck on your endeavor.