Are you guys saying that the Concept Guide Method is only good for the spinning reel that's used to line up the guides?

It will work better if used with the reel that has been used for the set up, but it will work with other reels of similar size nearly as well.

What you don't want to do (and there's no reason to do it anyway) is to replace a 1000 series type and size reel with a 4000 series and expect it to work as it did before. But if you set your rod up with say, a Shimano 2000 series type reel and then switch to a Daiwa 2000 series type reel, the difference in performance will be minimal.

..........

One of the things I do to address this issue for customers that do not know which specific reel they will use or are prone to frequently buying the "this-season's-new-best-reel" is to follow Rich Forhan's guidance in his article on Equal Distance Spacing that is in a back issue of RM (sorry, don't have it nearby to provide volume and date). I may lose some performance, but the finished rod still exceeds the customer's expectations.