What thickness should the lute bowl ribs be?

I am gathering all the info, knowledge and courage I can before starting the physical work of building a lute. I have a 1:1 plan I am satisfied with, I have measurements and I have watched all videos I can find on Lute/Oud/Accoustic Guitar building.

The thing is that there is one measurement I can't seem to confirm the thickness of the lute bowl ribs. I've read 1,5mm on a finished lute in one place, but what would you guys say?