Both Ocean Explorers and VI Dive are excellent operations ... personally I prefer the latter. There's a smaller outfit called "Technically Speaking" which is also quite good (and less expensive). You won't get all the amenities, such as on-board Nitrox ... but if your group's small, Cap'n Harry's boat is quite comfortable and easy to accommodate your itinerary.
From the perspective of someone who doesn't penetrate these wrecks, I prefer the Saskatchewan. It's not as physically imposing as the Cape Breton but it has far more life on it. My favorite way to tour is to swim from midships to bow, drop down in front of the bow (an incredible view looking back if vis is good), swim the "mudline" down one side to the screws, swim under the ship at the screws, ascend back to the deck, and make my way to the ascent point.
There are some other excellent dives you might be interested in. Two of my favorites are Snake Island Wall and Jesse Island.
Snake Island Wall goes quite deep ... and there's a huge overhang at around 110 fsw or so that's spectacular. But my favorite part of the dive is in the shallows above the wall (a great place to decompress for 25 or 30 minutes after doing the overhang). Making your way toward the island you'll encounter a lot of boulders and small ledges that harbor massive amounts of sealife ... octopus, wolf eels, many species of nudibranchs, and other cool critters. And if you come in at the right place and time, the harbor seals that call this island home will come out and play with ya. It's pretty cool.
Jesse Island is a diver's playground. It's a small island that's privately owned. On the westward end of the island is a dock ... and just past the dock is some incredible structure that's been carved by the tides out of the sandstone. There are caves and swimthroughs aplenty, ledges and overhangs, and generally a lot of stucture to play around in. The other end of the island is more walls, ledges, overhangs ... and tends to harbor more marine life (being the seaward side, I suppose). Avoid the middle of the island, as it's mostly just sand bottom. Depths on either end will generally top out at around 80-90 fsw, with a lot of the interesting structure in the 30-50 fsw range ... so you can get nice, long dives. This is a great place for a final dive after a couple on the ships.
There's no shore diving in Nanaimo to speak of. There are a couple of moderately interesting dives north of the city, but I couldn't even begin to tell you how to find them.
Have fun ... it's one of my all-time favorite playgrounds ...
... Bob (Grateful Diver)
