Sorry that is very... wrong.. the size of the housing greatly affects the resolution of the meter. grainy resolution from a sensor meant for a 55mm housing in a 90mm housing will not do you any good. The modern slot style sensor are much more accurate, the OEM have had a movement to HZ based metering over a 5v analog signal the HZ based will never run out of headroomI don't think bigger hurts much. Keep in mind, the meter has to have an accurate reading at idle with almost no air going through it. That's not going to change much on the cross sectional area of the meter.
I actually do not know much about tuning. I admit it. As I understand it, the resolution on the factory meter is good, but the response time is not. Does that makes sense? It seems to vary from one tuner to another. One tuner wants you to have a Ford factory meter, and then the next tuner is upset because you don't have an SCT3000. I don't know what to tell you. I know that in the before time, when actual computer tunes were rare, everyone just bought a big Pro-M or CNL meter, and it worked fine.