When does your secondary role kick in as an option?

I normally go support/jungle, which, not surprisingly, gives me short queues and routinely placed as support. Recently I've wanted to try a different role, so I went jungle/support instead. This leads to longer queues placing me as support.

If the subject question is hard to answer, maybe this one is easier: if I want to play a non-support role, do I effectively have to not place support as an option whatsoever? Presumably that would mean my best bet to be jungle is to choose jungle/mid, since mid is the role with extended queue times, but I'd need to be prepared to play it just in case.