I think the big question is when using a restrictor or not is who engineered the valvebody or shift kit. Timing of the 2/3 shift is the weak point of a 727, several things mentioned affect it, What I have seen is that many of these 727's have been is service for what well over 30 years? How many different times have they been built and modified, and how many people can recognize when rebuilding one what modifications have been done before? Plus a lot of aftermarket orifice plates have no markings on them to tell you if they are modified. So just to be careful any discussion on what number of springs to use depends a lot on whose components you are using and how many times has somebody before you drilled or restricted a passage, and how. I have fixed several problems transmissions, that the root cause of the failures were modifications done over the top of modifications.