Thanks for the reply. I will certainly share an image if I find one. The Sheridan was part of the Dramatic Line, a strange name for a shipping line. But all the ships were named for figures from the theatre, such as the playwright Sheridan and the actress Siddons (a ship on which other of my ancestors sailed to America).
Searching Google, I find references to the Sheridan and the Dramatic Line in a book, "The Western Ocean Packets" by Basil Lubbock. It contains an illustration of the Sheridan's sister ship, the Roscius, on p101 and the dimensions of the ship on p10. Google does not have the whole book but I'm getting it from the library. You might find it helpful too.