I'm interested in doing the park as shore dives, not by boat.
We did it once. Was a great day trip. Take a good amount of snacks and a lunch. Plenty of cold drinks, because it is a longer drive than it looks on the map, roads are not great.
The scenery and the dirt roads, though, really made the trip worthwhile. We saw so much of the island that I had no idea existed. It was a great day and the diving is suite different from the south.
We used the information from the shore diving guide to make our entries and that worked out well.
I remember seeing huge lobsters and rays. It's been several years but still remember those dives. There was some storm damage to the reefs but it was still womderful. Felt like we had the whole place to ourselves.
I didn't find the currents, entries or exits that difficult and I was a shore diving novice at the time. I was being led by my husband, who is an instructor and very experienced in CA shore diving. But, compared to Red Slave and White Slave, I'd say Slaagbai was about the same.
The sites just north of the oil facility are some of my favorite. We tend to divide our time between the far southern sites and the ones north of the oil facility. Then, for night diving, it's usually Oil Slick, my favorite night dive anywhere. ( although Catalina Dive Park is running a close second and might end up in first, we'll see after next week)