Is there any current existing design for reference? I would be interested to make a new frameset.
From what most of us read we look for:
Short reach (ex: canyon endurace, pinarello X)
Higher stack (ex: canyon endurace, pinarello X, etc)
27.2 seat tube
Light weight (ex: large and xl sizes with paint around 1000g mark)
Good look (aeroish). Like the speeder cycling r55/tavelo arrow
T47 bottom bracket
35mm tire
Price tag not higher than others
No copycat
I'd suggest as well have a preset of colour paintscheme. And as I mentioned in another post thst you could ship in the box groupset even if you don't provide warranty because it allows for reduction in overall shipping prices.
My last build was a velobuild r066 precisely because it ticks almost all these part. Didn't go for your grevil mostly due to pricing and because it was heavier