Allow me to explain. Reboot prefers to be pulled downwind by the jib. The Monitor™ wind steering prefers it too. And from a safety perspective it is much easier for me to reef the jib from the cockpit then go out on deck to reef the main. (Yes, a furling main would be great if I had the money.) Downwind if I put up the main it blankets the jib. So it is one sail or the other. It turns out that the 4th reef on the main (which is actually the storage pack for the sail) has enough windage to stabilize Reboot going dead down if I swing the boom out to the side. Who would have guessed?
Fair winds and following seas :)