Maybe I'm misunderstanding mclaren's example, but the graphic he posted has a number of notational errors. To wit:
in the third voice, if the meter is 11/8, then an 11:9 tuplet will not fill the bar, as it will only cover 9 eighth-notes. Perhaps he meant 9:11, in which case the meter needs to change to 9/8. Or the tuplet marking is superfluous.
Tempo indications would be needed for each voice to indicate different tempi, or dotted lines so that it's clear that you're dealing with poly-tempo/poly-meter rhythmic relationships. Otherwise, it's not clear where things should align.
Cheers,
A