As a rule of thumb, I'd say one cliché per [Romance]--and then be damn sure you can make it work. But if you're going to try to write the virginal amnesiac twin disguised as a boy mistaken for the mother (or father depending how well the disguise works) of a secret baby, honey, you better have some serious skills. Or seek therapy.
It is precisely, if paradoxically, because reversal is in the service of repetition (so as to ensure, alongside its companion strategies, a dizzying proliferation of citations) that it gains a subversive power rather than remain a mere dependent (and thus conservative) form of social discourse. Reversal plays a double role in this novel (MONSIEUR VENUS), for it is not only a formal strategy bearing on citation, but itself a citation as well; one more cliché mobilized from the fin-de-siecle reserve.