I was searching eBay and thought I saw a 1841 large o which sells for $600 in g condition and I researched the topic. I found out that it was not A large o but not a small o either. I continued research and found out a medium o was made in 1842 too. I still haven't found out how much its worth and would like to know. All advice will be appreciated.
I found this in the description of a Heritage auction listing: Variety: Fortin-104. Open Bud. One of only two Medium O die pairs for the 1841-O. A die crack between the ES in STATES and a clash mark near the M in DIME provide further identification. The 4 in the date is centered above a dentil. Heritage Commentary: Many Seated collectors currently pursue only those varieties listed in the Guide Book. In the future, though, mintmark size distinctions, such as the Small O and Medium O, may be widely collected with the scarcer mintmark sizes in demand. Open Bud Medium "O" 1841-O Fortin-104 Dime, MS62 Scarce Medium O Mintmark I don't know much about this series, but from a cursory investigation of the topic, it seems that the driver of the price is not the size of the mintmark, rather the use of a transitional reverse die that had closed buds instead of open buds. Closed Bud Large "O" Open Bud small "O" It seems that Heritage is predicting that collectors will eventually start paying premiums for the rarity related to the size of the mintmark.
Not 2 coins, 2 die pairs are known which is thousands of coins. Based on what I can tell, the medium "O" does not currently drive a significant premium over the open bud large "O". But again, this is not my series. For a more in depth answer, you are going to need someone who specializes in seated coinage.