You’ve got the right of it, although the odds of me every making an actual index note for “Comparing Egyptian and Sumerian royalty” are pretty low — it would probably stay a synthesis note unless I somehow do a lot with Egyptian and Sumerian royalty.
But I suppose if it came to that, then yea I would make an index note for it. I might broaden it out to just an index note for Royalty, depending on what else is in my vault. Generally speaking my index notes currently are very single-word in terms of naming structures, it helps me identify them faster.
As far as bottom-up vs top-down, the idea of making extra work for myself just to make sure that everything is linked to an index note feels very artificial to me; I imagine there are some use cases where that makes sense, but for what I do it would be a waste of time, which I am pathologically allergic to.
I use my index notes mostly as a way to keep track of concepts I do a lot with, but I do have a template I use for them.
Somewhat amusingly, because I do have a lot of notes related to Egypt, I haven’t actually bothered to make an Index page for Egypt because I don’t generally sit down and do much noddling about Egypt per se.
Here’s a screenshot that might help demo a little better.
The numerical prepending is because I use the Johnny Decimal system to help ensure folder order. I actually recently aligned it to my physical filing cabinet, which has been surprisingly helpful.
As for insights vs. synthesis, for me, insights are usually a little more … disconnected from a source than synthesis notes. Synthesis notes are usually where I summarize multiple pieces of information on a particular atomic topic, whereas insights are things I realized independently of the text.
It will probably seem like a somewhat artificial distinction just looking at the examples:
but for me it’s the difference between “ah yes, I have noticed that I now have several small notes in my literature notes about a very narrow topic, I should combine them into one top-level paragraph that pulls the information together” (sort of a very mini narrowly focused index I guess?) and “ah! I have realized a thing that was not told to me.” I generally use the insights as fodder for articles like this: 3 Theses, 3rd Thursday: Managing Things » Eleanor Konik
But there’s a fair amount of overlap and depending on what kind of person you are and what kind of writing you’re doing, you could probably just combine them into a folder called “claims” or something.
Hope this helps!