There are so many small differences in planes and pilot flying styles that I'm weary of the "set X at the FAF" approach. Numbers are important, but fly the plane first and foremost.
Sometimes 18 inches is what you need, sometimes 16.. fly the plane and point it to where you want to go.. say 500-700 fpm descent, set the power as you need it
I leave the prop alone.. if I need more power for go around they all go in at once.. if I need more RPM because I goofed, or ATC kept me high, I'll notch up the prop from 2200 to 2400
I was sitting right seat in an SR20 a few weeks ago with a recent check out and we got uncomfortably slow in the downwind to base turn at Hemet.. "dude, we're slowing down!" I proclaimed as we bled off from 90 to 85 knots in the turn.. at at 70 knots I nudged the stick on my side forward and left seat finally got the power in.. the explanation was "I don't get it, they said 17 inches downwind and 15 on base" .. I don't understand that. When did manifold pressure over ride airspeed and flying the plane. They can be a good rule of thumb but I wouldn't obsess over memorizing power settings.