Keeping in mind that I am no paint guru, and opinions on what shade is "right" are ... varied ... Deck Blue 20-B in either the June 1942 or March 1943 formulation did retain at least a vague bluish shade (to my eyes at least) while being very dark.
That said, and bearing in mind you are limited to what is in a spray can, I would suggest Testors Dark Sea Blue, FS 15042, and then perhaps darkening it a bit with a black wash on the flight deck, which might also heighten the details. Go here for the Testors paint lineup in FS colors: http://www.testors.com/category/136124/American_FS_Enamel_Paint which also notes what shades are available in spray cans.
On a side note, I build in 1/700 and when I do indulge in a camo scheme, have used Testors Flat Sea Blue 1172 out of the little bottle for Deck Blue 20-B. Close enough for me!