Hi Jim, I will be happy to help where I can. I manage my brother's Y DNA and my mtDNA at FTDNA. I started with 67 markers for my brother, then moved up to Y700 about 2 or so years ago. I communicated with Donn Devine, JD, CG about a year before he died. He managed the Baldwin surname on FTDNA because his wife was a Pennsylvania Baldwin. He did a great job of organizing the Baldwin surname by location (CT, PA, NC) based on their DNA. I originally contacted him because he placed my brother with the CT Baldwins and the direct Baldwin ancestor I was most familiar with was an early settler of MA. Donn explained that he included my brother with CT because they all had to have had a common ancestor given their DNA. He was absolutely correct!
Since that time, I took a genetic genealogy course through our local historical society, a seminar with Blaine Bettinger, and got a small bit of training in genetic genealogy via the Boston University course I took online just prior to the pandemic.
About a week or so ago, I was thinking about doing a 'Baldwin One Name Study' based on location of origin (e.g. the CT and MA Baldwins all came from the Aston Clinton, Buckinghamshire region of England. And now your idea is very similar and also based on the DNA subgroups.
Here is the issue, I think, with DNA subgroups, though. Most of the men from Western Europe are R-M269, which is what most WikiTree men have uploaded from Ancestry, 23andme, MyHeritage as atDNA. I don't know how many men on WikiTree have paid to have Y67, let alone Y111 markers that can help distinguish lineage.
Nevertheless, I think it is a good idea! When I updated my 7xGGF, Henry Baldwin, I actually added a section on Baldwin Immigrants from Aston Clinton and Common Ancestors. I think this is akin to what you want to do.
Here is the link to my Henry Baldwin: https://www.wikitree.com/wiki/Baldwin-5
You will also see this in the upper right corner, a member with haplogroup R-BY62081 based on y-700 done at FTDNA.
I mentioned that I manage my brother's DNA on FTDNA, Ancestry, etc. I paid to have his Y700. He is more than happy to have me list his DNA on WikiTree; however, HE would have to have a site and sign, etc. This won't happen because he is blind in one eye, and never (I mean NEVER) uses a computer, wants to use a computer, etc., which is why he has me manage his DNA (as a favor to me in my genealogical quests). I just had a G2G discourse about this very issue, actually, about a week ago.
At any rate, the person's Y700 is an EXACT MATCH with my brother's Y700. It kills me sometimes to not be able to upload his DNA and see to such matches. The WT member's Y700 is on all of the MA and CT Baldwins and their male descendants...just as Donn Devine had organized those Baldwin DNA studies! The WT member contacted me because he saw my brother's exact Y700 match on FTDNA and questioned the LNAB difference. The WT member has since added his line to WikiTree and until around 1700, his LNAB was Baldwin. He descends from the CT Baldwins. For whatever reason, perhaps adoption, his surname went from Baldwin to his current last name.
Kevin Ireland's email to you might suggest a similar issue with McCool (e.g., like Donn did, he organized Baldwin DNA into CT, PA, etc.). It could be that Kevin's McCool line may have a different common ancestor versus his cousin. I am not well-enough versed in DNA to that extent to know.
I will look forward to following this G2G post. I think this would be a real contribution to the Tree to distinguish between common surnames and DNA. Do keep in mind, as well, that there may be ethical issues that would need to be addressed with a One Name DNA subgroup.