As to Scharnhorst, I just got the book on her and her sister from Squadron. Granted it is a few years old, but the author said the Dragon 1/350 is the best one out there. I have the '43 version kit, and have looked it over. Very clean moldings, good detail, and a lot of PE, but not sure how much more might be needed. Have not seen the Trumpy version.
He also gives an overview of the kits available, and pics of built up models, along with the various suppliers of AM goodies for all scales.Also gives a history of both ships service lives.