Ok Chris. I finally got the mixes you need for Tamiya paints. (had to remember to do it, sorry, then find the instructions to my Missouri)
Navy Blue - equal parts Royal Blue (X-3) and Medium blue (XF-18) and flat base for sheen
Deck Blue - 4 parts dark Gray (XF-24), 6 parts flat white (XF-2), 3 parts flat blue(XF-8) and one part flat red (XF-7)
I have never tried to mix them, so I have no idea if they are accurate or not.
One thing you may want to try though. After thinning Polly Scale, add a couple of drops of Future. It should act as a slow drying agent and add a slight sheen to it also. Personally, I have the 155 also and I add two drops of Valejo slow dry to the paint prior to thinning, then thin with 70% isopropyl alcohol. And contrary to popular belief, I have never had a problem with it turning into goo.
Good luck & remember to mix enough to paint two ships, or you know what will happen