In my limited experience and observation, Mr. Kimura has a variety of apically dense, full canopied junipers as well as lighter and airy canopies with plentiful space between pads. I think trunk diameter, height, style of tree (also whether tree is masculine or feminine) also dictate density and fullness of overall apex.
A more slender and curvaceous trunk will most likely have airy branch and pad placement, showing off the trunk and trunk line of the overall tree, such as in a literati, allowing plenty of light and room for birds to fly through.
A masculine tree, on the other hand, with a commanding base and wide trunk tends to feature more density in the apex with larger and fuller pads (and “less space” for the birds to fly through). But as always, guidelines and standards are not hard and fast, “rules” are often “broken,” a combo of density and airiness may be present, and the payoff is spectacular.
Personally, the type of juniper apex that appears 2 dimensional, layered (with virtually no spacing) and has a helmet-like appearance and straight edge is not appealing to me, but subjectivity and personal preference are always at play.
As to division among masters, I’m sure someone with more experience and knowledge of well known masters can probably share some insight to that question. Most tend to be versatile from what I’ve seen.