The Complexities of DNA

The envelope with the DNA Kit

After a great deal of reading about the different DNA tests available I came to the conclusion that the Y test would be the most useful. I ordered the Y 37 marker test. The autosomal test is too general to be useful at this point. I decided to test someone in the line of the Forgey family I have established a circumstantial case for. I am hoping someone in my line will be tested soon. If this person decides not to then I will have my uncle tested.
I am not sure exactly how many generations back I might be able to go with this test? It seems from what I read it establishes a family relationship 8 generations ago with a high degree of certainty.  Hopefully there won't be too many mutations in the markers tested. Over the generations mutations occur occasionally . I am hoping for at least a 35 out of 37 match between my family and John Forgey's descendants.
I am hoping two tests will breakdown my brickwall. I have been searching for other male descendants of Andrew Forgey and Margaret Reynolds in case I need more individuals for my DNA study. I found out there were few male descendants in their son James Forgey's line. He had only one son. Their son John Forgey had the largest number of male descendants. Most of his descendants still live around Chattanooga Tennessee. I don't know where the descendants of Andrew and Margaret's son Andrew settled? They lived in the Shelby County, Tennessee area in the late 1800's. I am not sure if there are any male descendants living now? They don't appear to be in that area now.
I should have no problem finding males in the Andrew Forgey and Anna Roller line to test. There are a number of male descendants in that line. A few years ago someone compiled a list of all know descendants in that line. It was 42 pages and listed a number of males. This list wasn't even complete.
I have been talking about a Forgey DNA study for years. Finally it seems like I am making progress in that direction. I have found two, Forgie and Forgy, results already posted on the internet to compare with as soon as I get the results. Hoping for a breakthrough soon!