I have been thinking about this also. I decided Monday morning was probably not a good time as people would be busy getting ready for the week, perhaps in meetings and the like. So I wondered about other days. Friday probably not good also because even if they are interested they may have forgotted by Monday and may in any case be preoccupied by the weekend. In the end, after some thought I decided Tuesday just before lunchtime might be best for me. Some will get it then, others during the afternoon and some on Wednesday morning. So, I am trying Tuesday just before lunchtime at the moment.
