The military's "new" TTP's regarding mil-based optics aren't that new, they started phasing straight mildot scopes out more than 15 years ago. I did got to the Leupold site and I think I found two riflescopes that have a mildot reticle, the rest were mil-based TMR, PR1, CCH, H59, Tremor3, maybe I wasn't looking in the right places. I'm not sure how it is in other forums but most here aren't flocking to Leupold or grabbing one of their straight mildot models, if they do. Leupold has a well documented history of not really pay attention to the market and then getting dragged kicking and screaming into their half-assed attempt to put out a product.
But I digress
I think it's fine you're starting at the basics but the information on how to use a mil-based reticle is literally everywhere and applies equally to a mildot reticle, MIL-R, CCH, etc... I'm also not sure what relevance the duplex reticle plays in the discussion regarding mil-based reticles, there's way to work with it for long range work but it's germane to this topic.
I agree there can be a delta between true dope and the BDC but you lost me on that last part.
Again, I don't think there's really a gap, I can google "how to use a mildot reticle" and come back with a lot of results, like a lot a lot, on the order of 1.3M results. I am curious about the "advanced" techniques.