Dan,
I have the following:
Military Modelling January 1992 with a colour plate of uniforms and Jan 1994 with an article about several 54mm conversions .
Then there is a book "Deutsche Uniformen und Seitengewehre 1841-1945"
whose title is a bit misleading . It's actually a pictorial with 310 good photos with blow ups of mostly imperial german uniforms and has a good lot of marine uniform pics, too. The good news is that it is bilingual. ISBN is 3-934001-01-7.
Unfortunately I don't have anything deep or on operational history. However I saw a book about "Marinekorps Flandern" years ago so there must be something out.
Let me know if I can help you more.
Manfred