John,
Hi, I could perhaps have been a little clearer myself.
I see you have indeed been researching for a while, I found your previous post on this topic.
https://www.rootschat.com/forum/index.php?topic=806941.msg6659293#msg6659293 As I previously said I would treat YDNA as a last resort. And it can be a waiting game.
Do you have any matches with the Blake name with your existing test?
My own test actually helped in a similar situation, a family who appeared in America in the 1670’s they knew not from where. However still has not given a documentary link or further detail than a more solid region of origin.
As you have been looking for a while I presume you have looked at the Blake family surname project at FTDNA?
I had a look while trying to answer your question more fully.
You may well already be aware of the below, but there seem to be a few other people actively looking at this family on both Ancestry and MyHeritage.
So if you have not already a MyHeritage test may be of some help
This would seem to give parents or potential parents or relatives to try to build a match tree around.
William Blake, Elihu Blake, John Edward Blake m Lydia Gridley 1797 Connecticut, they seem to be in New York State in 1850.
On the same page as them in the Early Connecticut Marriages is a Thomas Blake and Sally Smith.
Finally if you do go down the YDNA route, personally I would go Y700, it is expensive, but it gives much more granularity. A definite small group of matches to work with and a specific haplogroup.
I upgraded mine to give that extra detail and it has certainly helped.
Hopefully this helps you make your decision.
PS I don’t think Ancestry to YDNA at the moment, so would not be additional money for them.
PPS I think the answer will probably lie somewhere in the very low cM match groups that Pro Tools allows you to see, but this is currently a very manual process. Roll on a proper cluster tool from Ancestry.
Happy Hunting