So, to be clear, my perspective is based on my use of the boat, which is almost exclusively for racing on the Great Lakes. On both of my boats we did end for end jibes and used a single set of sheets on the chute. The lazy sheet acts as the guy. We ran twings on both sheets, to control the lead angle of the guy, and occasionally on the sheet to choke down the sail.
We use a barberhauler to move the sheeting point of the headsail for improved sail trim when not close hauled. This is usually in heavy air reaching conditions, when we don't want to fly the kite, or on those rare occasions where we are racing in a JAM fleet.