This is definatly the time to make any furler ajustment, while the furler is on the ground. BUT FIRST, moving the mast step, will not change the headstay length.(see Bob Rutsch above)Lay the unit on the ground and measure pin to pin. Go to the boat and measure on the stem fitting pin to sheer line.(see By-laws and measurements on this) Add the two together and deside how much ajustment need to be made. The Furlex unit will give you about an inch of adjustment. Re- to you owner manual to see how to get to the spindal, inside the drum, of the unit. A standard unit will have about 1 inch of ajustment by turning the toggle stud in or out of the spindal assembly. The unit may have been put together with a "rigging screw" Furlex's turnbuckle(optinal). This will give you about 2 1/2 inches of ajustment. If your measurment is way off, to lengthen is easy, just add a toggle and ajust to the length you want. If you unit is too long by more than can be ajusted,(1) make sure there is not a toggle that can be removed, or (2) you can shorten the unit. At the drum, the headstay wire attaches to the spindal with a Staylok fitting. You can dissasemble this fitting and shorten the wire. Any amount you shorten the wire, you need to shorten the top extrusion as well. Look carefully at the manual before doing this. If you think this is out of your relm, get a rigger to do it. THE STAYLOK FITTING IS VERY IMPORTANT AND MUST BE PUT TOGETHER CORRECTLY. But I can't imagime this will need to be done. If the unit ia a few inches to long, you would know it now. Usually they are too short and will need a toggle. Once you get the length you need, sag is ajusted by rig tune.
My opinion is to be all the way back in the partners and max headstay. If you don't have a manual, let me know.

Gordon
Shaken not Stirred #258