We've sourced and built a few of these for customers of ours. They're a great bike if you're after an out and out race bike. As for sizing, you do need to be quite accurate because of the seatpost mounting. I'd get a sizing session before ordering one. You can do that through us, or if you've got Bike Fit measurements you want replicating, you can send those through to us via our website and we'll figure out your sizing and component choices 👍