My view is, do what your manuals say.
If the manuals are unclear though, understand why we have a stabilized approach. The idea is that from a certain altitude the aircraft must be fully configured, on profile, and on centerline, and most importantly, only require minor deviations in power and flight path to achieve a landing.
With that said, in your scenario I would make an assessment of the situation and decide whether I think it can be fixed by making a minor adjustment to the profile (did the papi only just go four reds or is the runway up near the top of the windscreen?) If I think it can be saved I'd call "correcting" and attempt to save it. If it became apparent that a minor correction would not be enough or if I thought it couldn't be saved I'd go around.
I agree with the general sentiment that if in doubt you're better off going around than continuing an approach you're not comfortable with.
Something else to consider with an NPA is that you have to expect to do some maneuvering when you get visual simply because the approach is not very accurate. If you have four reds at the point you get visual but you haven't descended below MDA yet I'd make corrections and reassess at the MDA.