When I had the Tohatsu, in a well ahead of the rudder, I couldn't leave the helm for a second before she would start turning in tight circles. Clamping the helm allowed me to go below for a moment, but no more.
With the Haswing on a transom mount to one side of the rudder, she runs straighter, I can clamp the helm and go straight enough for long enough to make a sandwich and a drink, but no more.
For longer than that, my wind vane will hold a course when motor-sailing to windward in light airs, but not downwind. With plentiful electric power now available, the answer is a small electric tiller pilot.
Ten miles at 2.5 knots takes 4 hours - the length of a watch that we used to have stand in the olden days, at the helm, glancing at the compass every so often, before self steering of any kind was available. Boring.
PS. When I bought Weaverbird, she came with a tiller pilot, but it had been wrongly installed and I couldn't use it - something to add to the winter job list.