does this get easier the more you do it or is it a new challenge each time around?
It's a new challenge ..... must find the right measures, tons of cab pictures and finally, stress Bruno

Are you handy with autocad or some other drawing software ?
No Etienne, everything handmade, I prefer this method and honestly I don't know how to use programs like AutoCAD or similar.
would be an idea to digitalize the cab plans, since the jakobud plans are slighty of measure as i recall
Not a bad idea, but at the moment I don't have the right equipment (scanner

).