Help sought: passages in which Nietzsche describes guilt as "useful" or "rational"

Ken Gemes (Birkbeck) writes:

I am trying to argue that while Nietzsche rejects what I call existential guilt/shame (that is guilt/shame that comes from experiencing one’s very nature as a violation of religious or other norms/ideals) he sometimes finds ordinary guilt to be rational and/or useful.  For instance in GM II 24 he seems to suggest it would be useful if we could have ordinary guilt about our unnatural inclinations, meaning something like our learned inclinations to moralistically repress our natural inclinations. Thus he calls for an attempt to “wed to bad conscience the unnatural inclinations, all those aspirations to beyond, to what is contrary to the senses, contrary to the instincts, contrary to nature, contrary to the animal”.  I would appreciate other examples that suggest Nietzsche sometimes finds ordinary guilt to be rational and/or useful.  Replies to k.gemes@bbk.ac.uk would be appreciated.