That's the only way I have done it with Klasskote, but my experience with K&B and Hobbypoxy would also make me say yes, white is required first.

Agree with Bill. Although KlassKote has what I consider to be really good coverage, any non-uniformity in the primer coloration will show thru in yellow if you use a single topcoat. And you sure don't want/need multiple layers of color.  The KlassKote white primer gives the yellow a nice bright color. Just touch up anywhere you go thru the primer before the topcoat. I have a Bonzo racer that I got lazy and didn't fix some of the primer before the topcoat and you can see it.

McDivot

I need to add to this discussion.  Currently, I am working on a semi scale stunt ship of a British WW II fighter prototype.  Calls for trainer yellow on the undersides.  The yellow from KlassKote is the correct shade per FSN (source is IPMS).  This yellow is a bit darker than most would use on a stunt ship.  Model is covered with .2 oz carbon matt, well sanded, filled with nitrate clear then KlassKote primer.  Surface was nice and smooth but the primer was not a uniform cover where the dark matt showed through.  I thought it would be OK.  Well, it was not.  The "splotches" showed through, required another coat of yellow, sanding and now ready to apply the next coat of yellow.  This yellow is heavy.

Highly recommend using the primer as a solid color as a blocking coat.  Or a very light gray on top of the primer.

Keith

Thank you all very much for your input.

Mike

With Randolph colors, white undercoat is REQUIRED for both yellow and red.   I learned the hard way when I piled-on coat after coat of red and still could see wood grain.

I guess Klass Kote is the same.

Incidentally, Pontiac made some hideous beige and maroon Gran Prix's in which they painted the front ends in the opposite sequence of the Fisher Body which was painted maroon-over-beige.  You could see the error from 1,000 feet away, or in a tiny black-and-white photo.