From the picture at the Naval Historical Center, it's impossible to tell what the sidewheeler looked like since only deck shots are available. The City Class Ironclads --see USS Cairo--lots of plans available --is not in the same group. The Hunchback was a privately built sidewheeler (what was original name?) and not government designed. Donald Canney is the authority on Civil War steam and he includes 1 chapter in his 2 vol work -see title below-- on the City Class but that is not, I think what you want. In vol 1, chap 8 Canney deals with double enders and includes some lines , body and deck plans buy these are Octorara Class, Sassacus Class, Mohongo Class--no City Class here. The source is
The Old Steam Navy, Frigates, Sloops and Gunboats, 1815-1885, vols 1 and 2.
Good Luck