The best dive I ever had in NC was on the Carribsea. Tons of tropicals, huge bait balls and lots of large sand tigers. I had a similarly excellent dive on the Atlas. Both were truly stunning - those particular days. I have also been on th Atlas with 8-10 ft viz, and in NC vizibility is extremely variable.
The Carribsea is fairly shallow so you can get a lot of bottom time, but very little pentration as everything except the bow has collapsed. The Atlas is deeper but has a lot of verticle relief so again long bottom times are possible.
The Spar can be very good, but in my experience the sharks tend to be a bit more skittish and you have to lie in wait for them to come back and if you are on a cattle boat with a total of 25-30 divers in the water, you probably won't see many.
As for the U-352, everyone should see it once, after that it is just a sewer pipe infested with Lionfish that have eaten most of the interesting tropicals. Once you've been there, news that the boat is going there is more or les a turnoff.
A 35mm film cannister works great for sharks teeth, but film and film cannisters are less common now.