Most dives were on Nitrox 30, but for the San Francisco Maru we were on Nitrox 24 for backgas (and whatever you wanted for deco gases). Interestingly, they are big believers in diving at 1.6 ATA for the deeper dives. Because as JJ memorably put it: "I have seen plenty of people bent, but I have never known anyone Tox, and I have never met anyone who has known anyone Tox." Certainly an interesting viewpoint.
But they will serve you whatever blend you want for any dive, especially San Francisco and other deeper stuff. My first week on board we were more of a "tech group" and there were only 7 of us, so we did a fair bit of deeper, longer stuff than a typical week.