I was thinking the same, and at one point saw something similar working but don’t recall how to do it again. If should be simple but needs a clear understanding to achive it. Hopefully one of our Gurus will step in and make it possible 
While that may be necessary, I’ve demonstrated that we can have relatively long books in TW, with each small section bookmarkable. See Bible Wikis — A collection of Tiddlywiki bibles. In each of those versions, each book, chapter, and verse is its own tiddler, and the performance is fine.
Yes, that is what I mean, rather than large tiddlers, sure large wikis (many tiddlers), although I am not sure if it solves the problem;