Kaiser he is a fine design and one of my own favorites.
Boat storage was indeed important, here is one of the highest resolution of of the fleet in habour with boats on davits..
click on image for higher rez
.during battle some boats were stowed below by hatches in the main deck, some left in port, and some were slung in davits for immediate use when underway as in this picture of the High Seas Fleet departing for Jutland:
and the Battle cruiser Squadron at the same time:
as you say they would be vanished in the first burst of fire for the muzzle flash of the main guns was tremendous, Railings were bent below as well for teh same reason. shell casings littered the decks and were very hot and would set boats on fire as well. I will find fleet at sea pictutes for you there are a few taken from Zepplins and other air service...
you think well about detail, my respects very much.
Sometimes a few lanuches were left on deck for rescue and work...when underway as here in this picture of the FdG
Here are rare and quite good photos of the High Seas Fleet at the height of its development:
and in this interresting film at 1:21 you will see a photo of a Konig Class BB at sea with boats on deck.
good detail pictures of the Derfflinger are what that film is about..which was a fine ship as well.
Finally some of the few actual phoitos from Jutland during the battle including one of the SMS Lutzow which fired the first shot from the bridge of another High Seas Fleet ship.