I have two shared ancestor (aka green leaf hint matches) to tiny trees - one was 113 and the other 114. They were long on both lines. For awhile, i had my maternal tree at about 350 people, but two lines ended in 1850 with brick wall emigrants from Ireland. The several other lines were long and robust to colonial america, but those short lines kept the overall size small.
No hard fast rules on size of match and success although i tend to agree that there are suprisingly fewer successful matches with very large trees, i.e. 20,000 and above. I used to get excited when i would see one appear but less so now after opening so many matches and having less success with giant trees