Hi Richard,
To take this a little bit further- as Geistware says its not uncommon to have equal throw yet have the travel not full synchronized thru out the full range. At our IMAC seminar a few years ago Rob Sarlan, Dave and crew discussed a) using Hitec digitals which can be programmed for travel speed and endpoint b) a bench jig with LARGE scale travel indicator c) having several servos on hand so one could pick ones that match well as there are significant variations in travel speed and intermediate positoning
So to some extent its a matter of how serious you are... if you want to discuss this more I be at the field both Saturday and Sunday
C U there I hope