That is very cool, but for a slightly off-topic consideration: I don't think I would want to travel at 60 km/h on a public road with nothing but an ultralight shell protecting me.
(Yes, I know bikers go much faster with even less protection - I'm not a fan of motorbikes either.)
Just because you can doesn't mean you have to. You can do 25-30 and put in 40W + whatever gravitational energy you need to gain (which will slow you down a lot on the hills).
But really, anything as efficient as an upright or more is fine.
One of the more efficient velomobiles that can be practical as a daily driver (ie. comfortable, has suspension, still efficient when open top so you don't broil in summer, you don't need someone to catch it when you stop).
Top tier cyclists in a pack do about 50km/h on the flatter stages on an upright with around 2x the power.