Form the point of view of authoring and maintenance (which is how you're asking), I do both.
I too use comments. For larger-grained tw-elements that need a lot of styling, I'll use dedicated tiddler-stylesheets for those. For "incidentals", (i.e. little nudges) I might add style elements inside a macro that needs them. I try to avoid <div style="...">
For the larger stylesheets, I typically use a sidebar tab dedicated to showing them as a list. Then, "muscle-memory" aids me finding what I'm looking for.
For the smaller guys, I tend to start in the browser tools inspector to remind myself what's going on.
HTH.