Hi Greg I have a copy of the "The German Battleship SMS Posen" Super Drawings in 3D by Marsden Samuel and Gary Staff. It has fold out plans for side and top profile in 1/350 and has hull cut outs on the reverse side. I think i bought it on Amazon. I can get a copy of 1:350 plans and you can enlarge or I can get enlarged and if you're willing to cover the cost plus shipping I can mail to you? Have you reached out to Ralph Coles in Nova Scotia? He made a mold of SMS Nassau which he more than likely has rib layouts. I bought the mold from him and later sold to Model Ships Ahoy. Let me know what works. Mark, Ontario, Canada
I have a pretty good starting point for a solid model of her hull scaled at 1:144 Fusion file or extracted OBJ Just uploaded it as a resource