Tips for hanging a Cado wall unit?  

I don't have a Cado wall unit...
I don't have a Cado wall unit, so I've never done this, but couldn't you attach the first mounting post, then temporarily hang a shelves top and bottom to the next mounting post, put a level on the shelves, adjust, and then attach that next mounting post. And carry on from there.

That's
pretty much how I hung mine Leif.
The shelves are notched out for the uprights, so it's easy to use them as a measure.

You're right. Sounds like a m...
You're right. Sounds like a multi person job. I'm married to a techie. Probably going to have to hire someone.

retro renovation
Read through the posted link.
And the comments. A few fellas posted their history working for and installing Cado units...
Lots of hints.
Locate a stud...
"Plumb level the first vertical, set it in and then use a shelf to make the correct space to the next vertical (as well as keep the shelf level) and set the next one. Just takes 4 or 5 arms?."
Read more: Poul Cadovius and Cado wall units: History and collecting guide - Retro Renovation
http://retrorenovation.com/2012/05/07/poul-cadovius-and-cado-wall-units-...

If you have a level
and a straightedge, and you know what the horizontal measurement is supposed to be between the verticals, you should be able to lay out the array with light pencil marks (white wall) or marked pieces of tape (dark wall), with a level line for the top screw of all the verticals. Then, if you know what the vertical spacing for the other screws wants to be, you should be able to place all the holes before putting any of the verticals in place.
Drill all holes, remove tape, place screw anchors, attach verticals, hang shelves.

Beware
the major issue is when your wall is not straight (while, of course, the elements of the unit are).
That happened to us and we were compelled to slightly shorten a shelf in width.
Measures doublecked and the verdict was: wall not straight!

Sprit level
Hi Keewee
Hang your first rail exactly vertical and fix it in place.
Use 2 shelves to place the next upright fitted to them at the bottom of the upright and top. This way you only need to hold the uptight with the spirit level showing you horizontal.
Make sure that you place the shelf support in the far left holes on the left upright. That way the edge of the shelf will be flush with the edge of the upright.
The right upright should have the shelf on the left run of holes.Always fit shelves next to shelves as you go along the wall.
ALWAYS fix the 2nd - 3rd 4-th upright by the very top hole so it will naturally want to hang vertical.
Easy once you have done it a few times.
Might be that your wall is brick so get some help to hold and mark