I've seen pictures of the Tusa but never used them. The 27 deg offset is a bit extreme but I suspect that the fin should work well. In fact, the idea of offset was pioneered by the Cressi company with their original "Rondine" open toe foot fin. In those days, the Navy divers used to swear by their "Duckfeet" which had zero offset but I could never get them to work well. The years came and went as did the fad of the ages, the Jetfin. This had a small offset but worked well because of the vents which seemed to compensate.
All of which brings us back to today. Personally, I use Apollo Bio Fins. These are constructed of wonderfully aromatic gum rubber, the old fashioned rain forest kind of stuff and feature substantial offset; not quite 27 deg, but a lot, maybe 20 deg. I wonder why it took them so long to come up with the split fin design. If it hadn't been for Nature's Wing, we'd still be puffin' on Quattros.
Personally, I'd stay away from the the split Jet. The fin blades are too wide for me. However, if you are above average in size, the split Jets do generate power. Don't know anything about the Oceanic except the V12 appears to be a copy of the Apollo Bio Fin. Rodale likes it.