What's wrong with using primer? They all do!!!
I never mixed anything with clear dope, but a tad of color dope mixed could have some advantages. I see no need to use nitrate also. But that's me.
You don't even need clear dope on sheeted areas if you really want to get technical. There's other products which are equally as good and possibly better.
You can start applying color paint right over primer without having a base coat of paint which has nothing to do with your color scheme. I forget because I pay no attention to it, maybe called a "tracer" coat? I believe silver is used.
Many modelers have great proven paint systems, but many are, in some ways, different, but in some ways, just about the same.
I like the system I put together and it'll take some serious conversations before I entertain a different one. Unfortunately, and as usual, this topic, finishing, brings argumentation. Which accomplishes nothing.