Don't make it more complicated than it is. Pt91, you can, if you elect to, always go down and have a look-see. YOu just have to be reasonalbe about it and use common sense. If it's socked in and nobody has gotten in in 3 hours and it's just getting worse, then when you happen upon it only to find the magical 45 seconds where the vis requirements are met, land, and you taxi into the FBO, I suspect someone will want to have a chat with you.Sorry to beat a dead horse.
So you pass the FAF and the weather drops below mins. You elect to continue and at the MAP you see the approach lights. Can you land under pt. 91? 121?
I understand that 91.175(c)(2) has not been met (flight vis. not less than the vis. prescribed by the approach being used), but what would be the point of continuing if you are prohibited to land?