There are cleats for reefing at the outer end of the boom? Maybe I misunderstand. I don't see how that would work for anybody.
I imagine it's not easy to get a 25 to hold a reaching course in 20 knots and waves. I would try letting the main luff until helm balance is achieved and then lashing the tiller in that position. But you already do that, no doubt. The answer is a tillermaster or wheel pilot. Fin keel boats just don't behave without some body or some thing to steer.
Nobody reefs with the boom amidships except at the dock, except maybe for small boats without a topping lift. It takes 15 minutes or so to complete the procedures, and you can;t stay head to wind in waves and wind. Generally it's a beam reach for reefing, where the sail can luff harmlessly beyond the cockpit and where the crew have full access to the gear at the gooseneck.
I may be missing something important in my visualization, but I would definitely not like to heave to, back the jib, reef the main and then have to jibe back on course in heavy air. I just posted a video of my own drill, let me try to find it. If you watch it, turn on YouTube Closed Captions [cc].