I have never dove with Narcosis, but I have been at the marina when they have departed....and from my observations its a cattle boat, take that as you will. Sandy's Sunday is a smaller boat with 10 persons max on the boat and from my experience usually less. They will go out of their way to accomodate special requests such as families diving with younger divers that want to hit reefs in the 20'-30' foot range to advanced divers wanting to hit much deeper sites. I did my advanced OW with Sandy and they had an instructor/dm on all dives, not just the training dives. That being said there seems to be many excellent charters in the WPB area and though I've yet to dive with them (hopefully soon) Hypnautical charters also seems to be a great charter.
I wouldn't call Narcosis a cattle boat. Any boat can get full to the max limit on a weekend or heavy tourist season. I have been all the West Palm boats when they are full and no matter what the boat conditions are a bit cramped. Narcosis isn't any better or any worse than the others when it comes to that. I have also been on Narcosis when there was just six divers so.......
Narcosis also uses a computerized display in their dive brief, which is thorough, so you have a really good idea what to expect and how the current is going to affect the dive. You can stick with the divemaster or you and your buddy can check things out on your own. One last note, the Narcosis is a fast boat which saves time going out and zipping between drop points.
If you are a bit rusty and like a more structured environment you can go with The Scuba Club. Easy parking and gear loading. Excellent divemasters who are incredibly helpful. I'd give them a call and talk to them about your needs. Very friendly op. The only caveat is that their boat has a platform for entry and exit as opposed to a ladder. If you have bad knees like me it can be awkward. 99% of divers don't have a problem with it.
Little Deeper and Abernathy's dive adventures are both outstanding ops. Friendly, helpful staff, good dive briefs et al. If you are worried about overcrowding you can check your dive on their websites to see how many divers have signed up and where the boat is scheduled to go i.e. depth, location, and dive objective. People can always show up and dive but you have a bit of a picture of what's going on.
Sandy's Sunday is an excellent op. I've been out with them a few times. On the trips I've been on they tended to go to shallower spots as they had students on board. She runs a very friendly boat. Dive interval included swimming and just having a good time. If you are worried about depth give them a call to see what their plans are.
As others have said you have to try the Blue Heron Bridge. Just check info for tides. You will know that you are there at the right time if you pull up and see people milling about in wetsuits and gear. And some guy runs up to you begging for and extra O ring.
One last note. Depending on where you are staying, Boynton is only 20-25 miles down the road. It is a fantastic dive spot. IMHO I think it rivals part of Key Largo. The dives on the whole tend to be shallower than West Palm. If you can check out Underwater Explorers for a dive. I can't remember if their minimum is 2 or 3 divers (the boat takes 6 with good room) and Kevin is one of the best divemasters. If you catch the black condos on a sunny day ................man.