Don, our 222/192 O'days don't have all the bells and whistles. They are fractional rigged, and as stock, there's an outhaul, a sliding gooseneck for luff tension, and end boom sheeting off a backstay pigtail. Many have also rigged a vang, and an adjustable topping lift (as mine has.) So, with a vang and good topping lift, it's possible to vang sheet, and have the TL control main twist to an extent, and leave the mainsheet for angle of attack without closing off the leech. Still not the same as having a traveller, unfortunately...
I have noticed that my backstay tension seems to cock back the top of the mast above the hounds. Looks kinda sketchy. I know of one guy who's 192 was featured in Small Craft Advisor who has rigged a 3:1 purchase on his backstay. One day I decided to see what I thought the mast would really do if the backstay were somewhat adjustable, so I tied a dock line to the backstay, and walked up to the companionway so I could sight up the mast. I pulled on the line, which deflected the backstay, effectively tightening it. Sure enough, with the swept spreaders of the uppers, the mast actually did bend and curve forward. I have decided that when I buy a new main sail, I'm going to have to rig a backstay purchase, because pulling on backsta would be a reasonably easy way to depower the main.
I'd love to have a traveller, too, but the only 2 viable ways come with drawbacks. Keeping end boom sheeting and rigging a raised bridge over the transom to clear the tiller would keep the traveler out the way of cockpit living, but it would make it more difficult to climb over the stern from the swim ladder, and I swim off the boat often. The other way is to convert to mid-boom sheeting, and run the traveller across the cockpit seats. The seats on these boats are very contoured, so that one would have to build up a bridge for the traveler to accommodate the sculpting of the seats, and then you'd limit cockpit livability. The seats are long enough I can lay full length, but with 4 or 5 inches of traveller raised up in the middle, I'd no longer be able to do that.
So, I just sail with vang sheeting, and I feel that's doing better than most cruising boats!