The whole attack party in the conning tower was a max of 11 people by the end of the war.
As far as radar goes, and looking at the Cod. The SD radar display (only range, no PPI) was in the control room. The SJ and later the periscope radar (was that SH?) has only one stool in front of it. So probably only one operator that controlled the whole set
Sonar, indeed that could be two, however, I think in the conning tower there was only one operator using either set (there is only one stool there). The other sonar operator(s) were in the Fwd Torpedo room.
TDC, indeed two,
Periscope two,
Firing key operator 1,
Helmsman is in the conning tower 1,
Plot at least 1,
CO who could also be the attack officer, or would 'drive' the boat (As Morton did on Wahoo)
Exec, who would 'drive' the boat, or who could be the attack officer (Wahoo)
Add a "Talker", a guy that communicates with the rest of the boat (but mainly torp rooms, and maneuvring)
I'm down to 9-10 now....mmmm pretty close eh?
I'll check with my resources.
Oh, and the radar operator would not leave his post when diving. He simply had tgo be there in case they would surface. And, with that amount of people there it would be a nuisance to have him squeeze through the crowd during an attack...
groetjes,