We were adding 10 hole adjusters to the original forestay systems after April 1995, not the Aussie. The lower forestay at 17' 6" (Since 1982) and newest shrouds at 18' 11" (Since April of 1995) left the rig too tight. You almost could not connect the forestay. When we came up with the longer Aussie forestay, it was supposed to be equal to the length of the forestay assembly plus the extra 10 hole. Somehow it ended up longer. That is the reason we reduced it by 4" recently to 19' even.

Yes the jib halyard tensions the rig. Although, as noted before, some sailors were rigging with loose shrouds and maximum rake requiring a longer forestay. They were light and it was really windy... they also kicked butt.