I disagree that each Viking operating off an airfield needs an extra however many people. Where I fly there is only one person driving the winch, there's a limit to how many retrieve vehicles you want driving around, only one person signalling to the winch, only one person keeping the log and the signaller is usually keeping the log. And the people waiting to fly drive retrieve vehicles etc. Our duty teams are 2-3 instructors and 4 other people, no matter how many or few gliders will be flying that day.