In FSM's first "Modelling the Second World War" There is a very good article on this model of the Bismark. According to it, the tops of the main guns were painted a yeloow/brown color very close to Grunbraun (RAL 8000) which denoted the particular campaign the bismark was fighting in. The tops of the little boats on the deck were painted to match.

The main gun boots were black and the main guns were a darker grey blue, almost schwarzgrau, but the turret matched the overall color. The non-wood decks were a similar schwarzgrau color.

The air recogntion swastikas were generally painted over or covered with canvas during operations.

Also, the article had a good idea for masking off the deck to model different colored planks on the deck. I can't see in the photos if you have already done this or not, but after painting the first color, add in a bunch of 1/16th inch strips of masking tape, then paint a slightly different shade, then repeat to satisfaction. If you have gotten to the point that this method is not feasible, you might try a reverse procedure to highlight just some of the planks in varying shades. The decks of the boats that are stored on the superstructure were also made from planks. Subtlety would be essential here, however, nothing too drastic.

A last suggestion the author had was to sand off the kit's anchor chains and add your own in. My own note here: cheap chains can be gotten at hobby stores that specialize in craft jewelry. Just find either the individual chains, or ask if they sell bulk chain cut to length.

Your kit looks good to me, but I am not a swabee by any stretch of the imagination. I hope this helps some.