Dan, Been a while since I personally rode foxtrotters (My wife still has one) but I don't seem to remember anyone ever worrying about the leads at any kind of walk. Pacing should not be a problem until you are trying to move the horse up into the fox trot. Riding them over poles or in long grass or in a plowed field usually seemed to help with that.
If you haven't already done so, you might want to check out the MFTHBA website. It is a good source of information for anything you might to know.
