Clarifying the Q survey

I must clarify that what the question is I wish to ask teachers introducing the Q hypothesis: What are you telling students the Q hypothesis is? because I suspect that not many teachers are persuaded in a single written Q source even if they hold to a two-source (Mk-Q) hypothesis. And I wonder are teachers are still telling students that the Q hypothesis is a hypothetical document even though they themselves may assume a modified 2SH with written and oral fragments comprising "Q". I recall my lecturers being quite confident of Markan priority but rather hesitant in what exactly Q was. I want to know if that was (ab)normal to teach "Q" is a "label" or umbrella term covering shared sources rather than a single document? Hence my quotes taken from Guthrie and from Barrett (and my allusion to Petrie's 1959 Novum Testamentum article). For example, how much of the double-tradition is considered oral traditions? Do oral traditions feature at all in what students are being taught about the double-tradition?

I have a suspicion that the survival of the notion of a Q document hypothesis is not unrelated to:

(1) What teachers teach about what is the consensus Q hypothesis,
(2) What teachers actually believe about the double-tradition,
(3) How teachers teach the Q hypothesis,
(4) What graduate students eventually take with them.

Are most students being taught that the standard Q hypothesis posits a single document?