Shared Matches below 20Cms

I persuaded a 1stC1R ( the last of his generation) to take an Ancestry DNA test to help solve an unknown common ancestor. However I have just realised that Ancestry only gives you "Shared Matches" down to 20Cms and ours would be much lower to be of any significant help. I have found some of the lower Cms matches to be very helpful in sorting out problems. Is there anything I can do, other than send my Cousin a long list of the relevant people with whom I share low Cms matches to see if they are included in his results ?

 

I think you have done the right thing to get a cousin to test in this case, especially as he is the last of his generation. 1C1R is not a long way removed and could have up to 425cM shared with yourself. So don't be too pessimistic, you may still find the grail you are looking for.
As for sending him a list of relevant low cM matches, it need to be very well targeted and you probably need to coach him in what to do. If you send him all matches below 20cM you would probably overwhelm him and switch him off for good. I myself have over 24000 matches from 6 to 19 cM, with over 90% of them in the USA, only 22 verified connections in that range, and many other hinted "common ancestors" where the hints are just rubbish. So you do need to be careful, but stick with it.

 

That sounds like something I might like to agree with one of my matches - we don't know each other but their father was adopted and from what I can see about our shared matches I have a good idea who their grandfather may have been. If I could see their other matches it might clinch it. Will suggest this to them, at a time when I know I'll have time to focus on processing the data.