Ah yes, the Good Old Days
Wow, it's been a long time since I even thought about a slab-reefed jib. The lapper on our former '81 Niagara 26 (hank-on, of course) came with a row of reef points. We tried this several times in big winds and waves and decided that it was not very practical for us. (Admittedly, this might work a little better on a large heavy boat.)
Comes the moment to reduce sail: You have to deal with a flogging sail on the heaving foredeck. Untie / retie the sheets without losing them over the side. Secure the new tack way up at the pointy and wettest end of the boat whilst repeatedly going up 4', 3' to the left, and 5' down...
The 20 degrees of heel will not help one darned bit, either, since you have the main still driving you on at least a close reach to keep the boat under control. The safety of the cockpit will seem like it's miles away in the howl of the wind and smacking of waves against the hull. The driver will be slacking off the halyard to your mark while you haul stubborn dacron down -- while trying to keep the boat on course and avoiding an unplanned tack
Finally, tie in the reef ties to the rolled-up sail, including the old tack and dragging clew with its heavy ss ring (or cloth and bits will hang up on the lifelines and stanchions when tacking. That waving clew ring may give you a whack just to get your attention, too.
It works, yes. After a fashion. For any significant time in heavy air, it would be easier, IMHO, to pull the jib down and hank on a smaller jib. You could, like traditional cruisers do, leave the old jib hanked on in a bunch at the base of the forestay and roll up and lash the "sausage" to a lower lifeline. Perhaps.
It's been a long time, so this "advice" is worth even less than the usual two cents.
Regards,
Loren