As explained here, you can schedule successive transition-driven attribute value changes on a single element [..] "using transition.transition, which creates a new transition whose delay immediately follows the existing transition" (a statement which seems to imply that staggered transitions don't work on single elements).
As explained in this post, however, "chained transitions (transition.transition) are implemented by inheriting the delay based on the previous transition‘s delay + duration, so, if you subsequently override the delay by setting it yourself, you’re still setting the delay relative to the current time, not the end of the previous transition".
As usual, I seem to have a special case: a single element (for argument's sake a circle whose colour is to be changed) addressed by a series of transitions of varying delay and duration. This means I have no choice but to set the delay and duration myself.
In sum, as far as I see, I can neither stagger nor chain the transitions: in both cases, each transition's delays and durations will be overridden by those of the successor..
As to examples, the closest I've found is this, which, though in itself useful, doesn't go so far as to cover my particular case. I'm at a loss how to proceed. Any suggestions?