Surely you'd get about 30mm back with the seatpost clamp stack height and the saddle stack height then if your measurement is to the top of the saddle? So the zipp would just about fit no? Maybe.
My bad, I thought the 240mm of usable post on the zipp meant to below the clamp but it's probably to centre of clamp isn't it... Looking forward to this build!
Surely you'd get about 30mm back with the seatpost clamp stack height and the saddle stack height then if your measurement is to the top of the saddle? So the zipp would just about fit no? Maybe.