The O'Day 222s came through with one triangular plate on the back stay which was used for connecting the main sheet to the end of the boom. My triangular plate had three holes in it and a 12" piece of stay wire was attach to the plate and the back stay chain plate. The back stay was attached to the top of the plate. I didn't like that set up and bought a traveler. I'm almost certain that O'Day used these same plates for some of their 25 and 26 sailboats, only they attached them to the side chain plates in the same fashion as my back stay. This was part of their mast raising system. They supplied a boom bridle that connected to the end of the boom a to a hole in the triangular plates on both sides of the boat. This kept the boom from flopping over. The rear mast Tabernacle pin was removed and the topping lift was attached to the top end of the boom. The main sheet was attached to the boom in the usual way, but the rope was removed from a sheave in each of the blocks to allow enough rope for the long spread of the blocks when the mast is down. With the back stay removed, the mast was pulled up from over the bow by using the main sheet plus one of the winches. This is the way it was designed to work. Someone on this forum had posted pictures of this from a manual years ago and I was hoping that they might post them again. Anyway, these triangular plates are attached to the lower or upper stays, I don't remember which, on both sides of the boat and when the stays are stretched up, they come even with the bottom of the mast and this becomes the pivot point of the bridles. What I did on my 222 is make up two pivot bridles and I added two pad eyes on my deck to attach the forward half of my bridles on both sides of the boat. I'm using a shackle connected to a side stay toggle on each side of my boat for the aft part of the pivot bridles. You could do the same thing to your boat, but the pad eyes need to go in the right place, or the bridles won't be even.
Joe