If you’re really interested, Brunnhölzl’s “When Clouds Part” is an excellent read on the subject. He has a whole section with summaries of how various Karma Kagyu masters have interpreted Shentong over the centuries. It is scholarly, long, and expensive, but well worth it if you’re interested.I have really come around to the Shentong presentation via the Kagyu presentation.
BTW the “Rangtong Ma-yin-gag” is the view that I’m leaning towards now. It has self-emptiness but with the universal positive qualities of Buddha Nature also—if I understand it correctly. There’s no separate Reality, which is the offensive Hindu heresy. It is mentioned in Situ R’s “Creation and Completion”.
To me the positive intrinsic qualities of Buddha Nature are what is important. Saying it is separate and Real is just adding emphasis.