When I started my DAR research many years ago I wanted to join on the ancestor a cousin used. The DAR now needs double proofs and things were less strict for proof in the 1890s so I would need to beef up the records. I didn’t have the skill sets at the time.
It was easier for me to choose a different ancestor. I went through all my charts and listed all the possible men. Luckily living in New England is very helpful. I used DAR sources at the Maine State Library. I listed all men that had been used in the past who were my ancestors. I then chose the man I felt I could more easily find records for.
This was all before the internet.