David Tyler wrote:... A line has also been added from the tack, around the mast (above the mast lift), and back to the tack. ...
I found the chafe and the taut grippiness of just such a line bothersome, plus it bent one batten, so I lashed a block onto the batten end at the tack, and rove the tack parrel loop (if you like) through that.
It adjusts easily with the resulting bit of loopy purchase, and a hitch.
And now swinging around the mast is effortless. For the tack, I mean.