FE cents were plenty popular with the public. The problem was the mint had difficulty with the striking; the head of the eagle especially would come out weak. The change in letters in 1858 was an attempt to address the problem, but it was not sufficient. Therefore the move to a new design in 1859.
I just noticed the over date in Coin World and it's not priced to high in very good at $100.00 but after that the price doubles with each successive grade. ( or more)
Get Rick Snows book #1 that covers the FE Coins. Probably the best reference. The High and Low leaf coins have been known for decades yet AFAIK they do not bring a premium when selling/buying as most are unaware of the varieties. Some are more scarce than others. See Rick's book. Info on scarcity may be on the Internet also. With 38 coins, you should have them all. BTW, check the berries as I did not see one of the berry types posted in the link. It may be a scarce type that the researcher is unaware of or I MAY HAVE looked at the link too fast.