I used to own a CV1800 in my home shop, then I moved. Now I've got on order a CVMAX to install in the shared woodworking shop of the new community where I'm living.
What measurement are you looking for? I thought you said you were trying to determine the height you needed from the top of the steel cross bar of the mounting bracket to the ceiling. If so, allow a minimum of 1/2" - i.e., the highest on the wall you should plan to place the top of that steel cross bar is 1/2" down from the ceiling. I'd put it at least 4" down to allow more vertical adjustment of the motor plate, and some breathing room for heat to rise up from the motor, but 1/2" is the minimum distance from the ceiling.
If there is some other measurement you need, tell us more and we can try to sort this out with you.