Folks can make the fertilizer issue simple or complicated. Brent Walston and Walter Pall use a regular chemical fertilizer, but it should contain micronutrients, the metals and minerals listed on the box.
On the other hand some people use organic feed, combination of several, combo of organic and chemical, organic with no animal waste, kelp and fish fertilizers, fertilizer in combo with humates, mycorazzae innoculations, a shot of micronutrients (w/o) fert., granules/cakes/balls/teabags and others I'm sure. Everyone can make a good argument for their approach.
I keep it simple, mir-acid for pines and a bit of plant tone (Espoma), which is inexpensive and readily avail. Here's a little something I learned recently in a seminar by Julian Adams. He recommends a dose of micronutrients (this product is not fertilizer) 1X year for white pines (which he grows and propagates). He stated it was important, especially for Zuisho JWP. (BTW, Julian Adams is also one of the excellent sellers and a good guy.)
I've read that people use inorganics w/o animal waste for highly refined trees and that it promotes a fine growth.
Personally, I think it's all good just prefer to keep it simple and inexpensive. Also, I don't have any masterpieces. I like your JWP.
central MD 7a