Being familiar with the C22, and jacklines, actually you have the right idea. Yep, just put an eye bolt near the winch point near the doorway. Make sure it is out of the way to walk, or you'll curse it, remove it, never to be used again. Ideally you want to clip on when leaving the cabin, and remain that way to the helm. Going for'd should take another line. These lines should be as such that if you flat bust your ass on the boat you can't go over. Fall in with an unattended C22 it'll round up quickly if you go over. But really. The whole idea is to STAY ON THE BOAT. Once in the water, bad news. If it is on autopilot and no one to stop it, cut the tether and take a deep breath. Of water. Get it over with.
Take your boat underway, and tie ANYTHING to the end of a line and throw it overboard. A sack, bucket, old rags, a kite under the keel, whatever. Now gather a bunch of this junk until it weighs 170 pounds. Throw it over. I will at this point advise you to have good cleats.
For that matter, try it yourself. Have the mate move the boat at ONE KNOT, while you troll behind it on a ski-rope or whatever. Get back on the boat.
Sure the very athletic of some of us can do it, but really.
No, if you're in the water, there ye shall remain.
Tight tethers; are happy tethers.
Nuther thing. Consider the dynamics of a line. Some boats that have very long jacklines are silly. Attached firmly on a for'd cleat and to the base of a mast, the right amount of linear force would jerk the mast base clean off a tabernacle. Same thing for every stanchion and lifeline on the boat when the slack took up.
Oh yeah, sorry for the rant. I just see to many "offshore boats" with the silliest looking crap called 'jacklines'. A nice bow-eye securely placed will work fine. Right above the cockpit drain points on the side would work. You can't get your feet in that corner to kick it.