Hej Lars
The 7T11, 7T11A, 7S12, 7S11, 7CT1N, 7A22, 7A13 etc. work just fine in a 7104, 7904 and 7603. However, the 7904, 7603 might be a better choice since you don't have to be so afraid of burning the tube and the plugins don't need the fast bandwidth.