I want to send some QSL cards for contacts I've made while portable/horseback mobile and thus could not have written the details down immediately. I remember the callsigns and reports, and everything was on 2m FM, so I've got most of the data, but one bit I don't have is the exact time. I could probably narrow it down to the hour, but not further. Is such a precision acceptable? Generally, how accurate should the time be on a card?
And while we're at it, if a QSO is prolonged (e.g. a ragchew), which moment should I log as the time of the QSO? Beginning, end, or otherwise?