This is the most common way of flying a burgee. You'll need a small stainless steel eye strap which will be screwed or pop-riveted to the bottom of the starboard spreader, half way between the mast and the upper shroud. Attached to the eye strap is a micro block. About 2 to 3 feet off the deck, attach a shroud cleat to the starboard upper shroud. attach it so that the cleat faces towards the mast, so it will not foul the genoa when tacking. Buy some small polyester line (or 1/8 dacron cord) and run it through the micro block on the spreader, then back down to the shroud cleat. You can tie the line so it's a continuous loop or tie small snap hooks on the end of each side of the line, which attach easily to the burgee cringles. Once the burgee is hooked on, run it to the top and cleat the line off on the shroud cleat. Our Association burgees are constructed of very durable materials and will withstand the elements well. Many sailors in my marina leave there burgees up all year long.
West Marine sells a spreader halyard kit for flying burgees, and there are kits for flying it on the upper shroud itself.
Official Catalina 25/250 national Association Burgee