I'm in the do I want to do this stage.
Coming from a guy who just set up a 6 pack dive operation from ground zero to running full time in 2 years, I am highly qualified to give this advice:
Make damn sure you want to do it before you start.
I am having the time of my life and I love it, but it is totally different than I expected. My diving experience came from running trips with my friends, guys who I knew were self sufficient and solid divers. I got to dive, and spearfish and actually drink a beer afterwards on the ride home. I am sure it is much like your experiences.
Now I have to deal with divers that I meet for the first time at the dock. I have to assess their dives skills by watching them set up their gear, asking them questions and talking to them, all the while being nice and using good customer service skills. Sometimes I have to do this with people that I would NEVER hang out with or dive with. I can't dive unless I have another Captain on board, and sometimes then if there are any marginal divers in the bunch, I still don't dive. If I take people out and it is rough and they get sick, sometimes they blame me or the boat. If the visibility sucks, it is my fault. If they can't find grouper on the ledge (and I know they are there) it is my fault.
This hasn't happened to me yet, but I am sure it is coming at some point. If something goes wrong, you will get smeared on the internet. It may be true, it might not. If something goes really wrong, you will get sued. In the case of the latter, you better be in 100% compliance with every USCG regulation, or not only will you get sued, but you may face CG fines.
Like I said, I am enjoying it and glad I went to the trouble to set it up. But it is not a casual endevour, and not all fun and games.
Did I mention you spend more money than you take in?