I sail J-24 "GIZMO" at Brookville Lake Ind., and have some questions about rigging. Anyone have advice?
I have a J/24. 1985 hull # 4098
Here is link to a website for tuning a J/24: J 24 Tuning Guide
I found that you should have the mast set back as far as it will go. The other most important things are that the mast is straight (it is very easy on a J/24 to have the tension on the shrouds set to make the mast bent the wrong way: to starboard or to port), the mast is slightly racked back, and the tension on the shrouds are equal. I have the outer shrouds set at about 25 and the inners between 15 and 20. When I bought the J, it came with a Loos gauge - a very good measuring tool to have.
Looks like new ones are about $70, but I bet you could find a used one (or borrow one).
Loos Co. - Tension Gauge: Mauri Pro Sailing