The mix formula is available, the only people who tell you otherwise most of the time heard it from the dealer. I recently had the local dealer call wanting the paint code for my Typhoon Maroon because they knew I had done some paint work on it, and THEY KNEW Harley had never released and CVO codes, when I told them it was a std PPG code they really didn't believe it. Give the PPG guy another try. If you don't feel comfortable with the PPG jobber ask him who in the area uses his products and sprays Harleys. Then talk to that guy.
But on that large flake color whoever sprays it for you will have to do it EXACTLY like PPG says or it will not match. All the steps are necessary, from mixing to spray pressure and gun nozzle size, unlike blending a fender on a new Malibu.