Do you have a Harbor Freight in your town? Between the wife and I we have 6 sets of shoes and I would suggest you do as I did and spend $16 on a digital caliper (
http://www.harborfreight.com/...taf?Itemnumber=47257). While obviously this is not a professional level tool, it is more than adequate for this kind of task and while you are out shopping for the caliper, stop by the LBS and pickup a new set of cleats as well. Using the caliper, you can measure fore, aft, and lateral cleat offset very precisely and with a new set cleats in hand, you can use the existing shoes as a reference although the first time you do it, if you are nit picky like me you will find it takes a bit of time as you will make a lot of small follow on adjustments.
¯\_(ツ)_/¯