I strongly recommend the White Ensign line of naval colors. If you're going to spend that much time and money on a ship model, you might just as well put accurate and quality paint on her.
The instructions for Yorktown are suspect. Her Measure 32/10a design scheme called for 5-L Light Gray, 5-O Ocean Gray, and 5-N Navy Blue. Flight deck colors would have been Norfolk 250 stain, but there's some speculation that the tone was darkened to match 20-B Deck Blue, which is used on all horizontal surfaces such as turret tops, catwalks, etc.
Regards,
Jeff Herne
Modelwarships.com