I submitted the five selected T Tau stars for monitoring. You suggested the Wright28 if I wanted monitoring in Halfa (line) and/or Halfa (continuum). I do prefer this (submitted as so). But as you mentioned in your reply, T Tau stars tend to crowd together and for three of the five submitted stars (DF Tau, V773 Tau and SU Aur) there is no suitable comp. star in the 14' x 9' FOV of the Wright28. So I guess I will have to quit the Halfa option on those three. The SRO50 will have a big enough FOV. Is the filterwheel carrying the same filters as the SRO35 (CUBVRcIc)? If so, I'd go for all five of them for DF Tau and SU Aur: these are CTTS: they should show large amplitude fluctuations in U-band). For V773 BVRI will do.