Some Tug pilots I can think off still practice this technique today---albeit from ground level !
However, I would be interested to learn about what sort of weak link was in place ( if any ) and the projected take off run for the Horsa--which must have been fairly lengthy I assume as it would be a heavy beast to get airborne in a hurry. The loading on the structure must have been decidely high as well at the moment of snatch--all credit to the guys involved though.