I asked Yishun directly what the measurements for the front end components are.
Here's their answer for anyone who's interested:
"For R086-D carbon framesest, the cable cover height is 15.94mm, headset top cover height is 17-17.4mm.
Usually we will supply 1pc 5mm height and 1pc 10mm spacers to customer together.
Please kindly check attachment again ( ignore integrated handlebar in the picture ), you will understand it clearly.
We can supply extra 5mm or 10mm spacer to you again if you need."
So, like Patrick said, you basically need to add 3cm to the stack figure of a given frame size. That is where the cockpit goes - one piece or not.
Also, they told me that the minimum required seatpost insertion would be 1/3, which amounts to 11,5cm of 35cm. So keep that in mind to determine whether you can actually set up the required seat height for a given frame size.