It seems to me that David’s and my view on what makes a sloop JR good, are nearing each other, at least on a few points.
My last two rigs for James’ boat have a much higher AR and lower chord/wl. ratio than any of my former rigs. The chord/wl. is only 0.72, while on Ingeborg and Johanna these numbers are 0.80 and 0.84. Downwind steering of James’ CD28 should therefore be quite easy, even without shifting the sail forward.
On the sail with 65 yard angle, the halyard/mast angle will be 16° - right in the middle of David's ’window’, and for the same reasons as his.
I regard the shifting of the tack of the sail forward as a possible plan B, but frankly, I doubt that it will be needed. Instead, putting in a reef will ease the helm without losing as much as 0.5kts.
No rigs like foolish handling. Sometimes they kick back, and the bigger they are, the harder they kick. With any new rig or boat, one should have quite a few shake-down sails to sort out handling and learn to stay out of trouble. Then and only then is one ready for deep sea voyaging.
One little warning to the beginners and wannabes in the JR business:
I and David may sometimes express ‘firm’ opinions on what is the best version of the JR. Lean back and relax; don’t let us scare you away. Almost anything goes. David has crossed big oceans with both super-high-AR and super-low-AR rigs, with yards being almost flat or next to vertical. That man can make any sort of rig work.
I have stayed in the more modest league, with sails well within the Hasler-McLeod tradition, and with 99% of my focus on coastal and inshore sailing.
Both David’s and my rigs have proven to be capable enough, inshore and offshore, so it is more about details and what your eyes prefer.
Good luck!
Arne