I been kind of on the fence myself with sail configurations so maybe someone can give me some advice. I am still not sure if running only a full main with no headsail in higher winds (say 20+knots) is more effective then running a headsail only. Usually I pick one or the other and most of the time its a full main by itself because its just easier to deal with since I have not upgraded to RF yet. I sometimes think one headsail without main could be the better choice. Then I also wonder if a reefed main with a 110 jib is the better configuration. I do get satisfying speed with the full main alone. I guess I need to just keep trying different setups to see what is the most effective. Maybe someone else with an Oday 22 or similar can give some advice?
On a masthead-rigged boat, the mainsail helps the boat point to windward, but the jib is the sail that generates the most power. In light to moderate winds, the mainsail alone doesn't generate much speed, but you can sail either to windward or off the wind. In stronger winds, the mainsail alone can generate fairly satisfying speeds for casual sailing. If you'll watch the boats queueing before the start of a race, most of the boats will be sailing on mainsail alone, and you'll see that, in stronger winds, they are moving quite well. One particular advantage of using the mainsail alone is that it is self-tending. You can center the traveler and tack back and forth without having to pull in many yards of jibsheets each time. It makes singlehanding much easier, especially in stronger winds.
If you want to sail on the jib alone, you should use an overlapping jib, about 130% or larger. If the jib is too small, it will be difficult or impossible to tack the boat, because a small sail, with all it's effort forward, will pull the bow downwind. A larger, overlapping sail will help push the stern to leeward, which will help the boat point to windward.
But, while either sail can be used alone under certain conditions to give a reasonably satisfying, casual sail, the plain truth is that sloops were designed to perform their best with a balance
of mainsail and jib, and, if you need the boat to perform well in difficult conditions, the best choice is a balanced sailplan.