So long as you do 20minutes in each hour slot, you'll avoid the surcharge, and even then, I've never seen it charged.
Last summer I saw two guys take an PA28 "out for the day" - they flew to Breighton and back, and then got Mike behind the counter to split the cost between them. (20 minutes each)
As for busy Saturday afternoon, everytime I've rung up recently, I've always been able to get an aircraft at short notice.
Make a trip of it to somewhere else and call in on either leg, or both? (or come with me
