3 coats of thin followed by "enough" coats of medium to get the thickness build up that when sanded will result in a good fit to the components. Whether it's 6 coats or 16, the fit is more important to me than thickness of the finish.
This thread has been quite interesting to read on the various application methods. For me, I use 4 thin applied with good finger pressure. Sand most of that back and then 8 coats of medium.
2-4 coats thin, depending on the porosity of the wood - I want a complete covering of thin to start with. Then 3-5 coats of medium depending on the situation.