Dan, 845 and 211 have diferent specs in terms of output transformer impedance, high voltage power supply, bias supply and plate current.
An 845 to 211 conversion is not trivial and a very dangerous project, due to the extremely high voltages inside the amp.
Maybe you should re-consider Cary's offer.
However, 211 tubes are less linear and put out more distortion than 845 tubes, which were designed for audio.
Unless you really need to use 211 tubes, IMO 845 is a better sounding tube, there are plenty on new production tubes that sound good (Shuguang 845B).
good luck
An 845 to 211 conversion is not trivial and a very dangerous project, due to the extremely high voltages inside the amp.
Maybe you should re-consider Cary's offer.
However, 211 tubes are less linear and put out more distortion than 845 tubes, which were designed for audio.
Unless you really need to use 211 tubes, IMO 845 is a better sounding tube, there are plenty on new production tubes that sound good (Shuguang 845B).
good luck