It also depended on the competition. For one, around 1967, I was at Waddington and had a good overview. The competition low level route was embargoed. Canberra were tasked with target recce and boxes of imagery duly arrived on the station. Sqn Ldr Wpns decreed that the Waddo sqns would work as a wing. I don't know what Cottesmore did.
From the imagery target offsets were selected and offset values calculated by several crews to get the most accurate values. I don't recall results.
A year or so earlier 3 crews, sqn unk, took part in the SAC bomb comp. Results were displayed on huge blackboard in Cottesmore Ops.
Later, in Cyprus, on 35, one of our nav rads went for a touring holiday around targets and offsets. On the day he parked his Volvo on a target.