Hey Lars, I am pretty sure 146.05 mm is correct (5.75 inches), as in this excellent article you mentioned previously in this thread: http://www.mycockpit.org/forums/content.php?r=165-Hessel-Oosten-s-Panel-Building-Focussed-On-Dimensions
Good job thus far triise! I'm just starting out my own pit as well, scouring the forums for tips and Ebay for parts - there is an immense amount of info to digest! Looking forward following the rest of your build.
Thanks for the update Deadman. I'll put this 'order' on hold for the moment, and try to source some knobs from somewhere else. I might very well be interested in full (or partial) sets, once there is enough interest.