Unfortunately, you taking a Ydna test won't help in showing a match to John C. McCoy since there is a female in the mix.
Your best bet would be an autosomal dna test--like the one
here or at 23andme or ftdna. But both you and the other descendant of John C. McCoy would need to take the test. Price wise, ancestry is probably your best bet for your purposes right now.
Hope this helps.