Hi!
This has been in several fourms and in much dicussion. There are actual US Navy color photos of U-505 at the time of capture. The hull and tower are definately darker than Dunkelgrau 51. The photos are closer to Blaugrau 58/1 hull with a Blauschwartz 58/2. Schlickgrau is too green. It was used on U-505 on an ealier date however.

The other issue is that of paint and scale. At 1/72 these colours are very dark. I am in the process of building this kit. I myself am going with a Dunkelgrau 51 upper hull with a Blauschwartz 58/2 Trum . The reason for this is simple, The darker colors don't provide enough contrast for the viewer. Just my thoughts, I have been building for over 50 years. And I have had several models in IPMS Conventions.