This document may help.
http://www.researcheratlarge.com/Ships/SS/1944JulySSCamouflage.htmlSome nice illustrations.
Some stuff I have notes on.
Black System for Subs
Entire above waterline black 82 all parts visible from the air.
Till early 1940 above waterline was standard #5 Navy Grey (Pearl Harbor PH Blue or Black)
PH or Pearl Harbor Blue was experimental, unfortunately it was not color fast and would turn milky very quickly.
I just read that the Navy is once again trying the color out.
I've even seen bright blue and green on a nuc in Lt blue water.
June 1942 Measure 10 - 5.0 Ocean Grey
Mid 1944 Measure 32/3SSB (Lt Camo)
Black all horizontal surfaces
Vertical surfaces having a grades series of greys ranging from lt grey to black from bow to stern
Measure 32/9SSB used a darker range of greys.
More effective for surface ops in clear weather and while submerged.
Deck weathering from gloss black after 6 weeks of salt water, spray and sun decks would bleach to a slate grey, somewhat blotched.
So there are a few different "Grey" schemes that the boats could have had.
Modeling colors
Dull Black - Flat Black
Non Skid Black - Semi Gloss Black
Not sure on the greys but White Ensign probably does have the correct colors.
Probably Ocean or Haze Greys.
Look though this forum to see what others have used also Fine Scale, Sub Committee, Hyper Scale.
Eric...