I'm sure you'll get it right. It's gonna be trial and error. Doing the color tests on the tape that you'll use is the right thing. You could do the color mixing on a white plastic lid, then apply the paint to the med tape only to find that it looks slightly different on the fabric.
Great looking builds. In November of 2012 I had the pleasure of meeting Mr Barillaro who owns a red Chrisman's Comet (if memory serves me right). I have some good pics of it I can send you.
The painted parts, the mock ups, all of it looks great. I just got caught up on this build. It has inspired me to dust off the bench and work. Great stuff Chris. Thanks. The Camino also is awesome looking. Didn't know you had one.