Hi Tom,
Disregard the Trumpeter instructions. Those are not reliable, and Trumpeters in particular including their illustrations. While there are a number of reasons, since the accurate information is available, use that.
Anti-fouling is a range of colors. While there is some similarity within navies as they used the same shipyards for both construction and maintenance, even there you see variation.
I've tried everything from boxcar red (brown oxide) to bright red. This is one area where I think spray can paint is useable. It's a lot of area with a uniform finish. I think smaller ships (corvettes and destroyers) look good with brighter red, larger ships look better with dull red. I've seen specific color call outs for Bismark, other ships tend to get a more general description.
Each Navy has it's own color system. Each is different. This is where some research will help your model to b something special.
I think the best place to start is here: http://www.shipcamouflage.com/
Go straight to paint chips to see the Royal Navy and Kriegsmarine colors. Hood is covered in Royal Navy Set #1. Bismark is covered in Kriegsmarine Set #1.
Here's a source for Hood:
http://www.hmshood.com/hoodtoday/models/tips/hoodpaint.htm
Modelmaster sells 507A Dark Gray.
Here's a source for Bismark:
https://www.bismarck-class.dk/paint_schemes/introduction.html
RAL 7000, 7001 and 7024 are available from White Ensign or other sources. I don't know about Modelmaster, but you should look it up.
Both ships had natural wood decks. Tamiya Deck Tan is a good place to start.
Certain areas which were steel or a composite are in other colors. Try to find diagrams. These include horizontal steel surfaces and some of the bridge decks.
I hope this is helpful. Have fun!