from my experience the pineal works really well for Tapeworms (could be that is because Newport created this one when he was dealing with tapeworms) or ascaris
otherwise I think if you know what is the main problem at any given moment, treat the specific critter - that is what I do and it works well
doctrine runs in the background regardless what frequencies you run and sometimes it is best to get quick result with the specific frequency - that is again my own experience
because if there is a match between the frequency and the pathogen then the winning = getting rid of the monsters is a beautiful experience (kind of like a marriage that works...)