I've got an extra Reflex I may experiment with. Right now, I'm thinking lower the seat, slant back the windshield, maybe narrow the handlebars.
Next would be a tapered tail section. Side fairings would be more complicated, maybe something that hinges out to some degree to allow feet to get down, then the wind blows them closed once underway.
I would see how much difference this makes before making gearing changes. Probably car tire and heavy rolloers first.