Actually, the car is not a
Actually, the car is not a hydrogen fuel cell, but a hydrogen BURNING vehicle, so it would achieve its top performance when running on a hydrogen-heavy fuel mix, which has a much faster ignition and burn rate than does gasoline vapor. Hydrogen alone is inefficient in current valve and piston combustion engines, so H2 alone wouldn't do the job as efficiently for top performance.
I'm kind of surprised to see Aston spearheading this since Mazda is the company with the most experience fielding H2 burning cars.