One thought I had about this recently. As I was reading the The standard zeros - #12 by interrato with the alternate system, I needed to write it out on paper myself to follow along. It’s one of those things that makes sense intuitively, but the notation for it is hard to follow because you have to record things in so much repetitive detail (just like double-entry bookkeeping).
I thought it would be worth exploring how it’s standard locations that is what is of value to humans. The numbers are great, and in a sense the essence of the system, and yet they also distract. I keep thinking the primary function of the numbers in JD are to make sure things sort and nest, and to make sure everything gets a unique ID. Essentially: numeric space behaves like regular predictable 2D space, while alphabetic space can warp unexpectedly. 
=-O
I don’t know what the right balance is, but maybe focus on the standard names first, since those are standardized too, and introduce the numbers later. ‘Every category has its inbox, archive, WIP at the start … and every area does too, you put things in as specific a place as possible now, and move it to a more specific place later.’
Here’s a bold thought: given the right tooling, a user of JD should be able to never use the numbers. The right tooling would ensure that they have max ten areas with max ten categories, and each new thing created in a category gets a serially increasing ID. The numbers are still essential, but would be created under the hood. After all, the use of the index to find things by name is the main way of interacting with the system.
And yet I get that somehow you have to explain the decimal stuff because that is what makes it work, and what makes it unique.