The 5.5 mm spokes don't fit the 20 spoke hubs, only the 21-24 spoke hub set. These are heavier, the spoke insertion and retention method is less reliable and potentially dangerous and the spoke count is just unnecessarily high. The 3.2 mm spokes that do fit the 20 spoke hubs are much worse aerodynamically. Shallower, thicker and a completely unoptimised cross section. The 5.5mm spoke also has fairly long cylindrical sections on the ends, worse than some alternatives. This is another aerodynamic penalty.
Ornan could very easily get their hands on spokes that could remedy those critiques a little bit. They don't seem to be too keen on updating their site, maybe they do offer more on request.
I've run some cfd sims on these profiles, not enough to be conclusive, but I haven't been too impressed so far.
