Each tuning guide has something to offer. After many years with the same sailmaker a change required us to make some adjustments. For example a straighter mast fits the luff curve of the UK main, while the North looks better with a bit of pre-bend. My rule of thumb is a new main or Genoa means a visit within the first couple races from your sailmaker.
Mast step 1" from molded step, J at 11' 6", and max headstay is standard to get rake and helm right. Next time your rig is down, measure the headstay from the upper eye to where the swage ends above the turnbuckle. Then when you set the length you will only need to measure the last foot or so from the stem to this point instead of trying to hoist a tape measure up the mast.
As you tune, center the mast tip using the main halyard to a point on the rail. Use the stanchion base just aft of the chainplates, but measure to be sure both are equidistant from the bow. As you tension, eyeball the mainsail track and adjust the shrouds so it stays in column. It's fairly easy to see if the mast is straight.
After many years of always using max headstay it's now a rare light air day with no chop that we don't tighten along with the shrouds. It's not an exact science though as we often adjust the rig without changing the headstay. You also have to account for changing headsails.
If you plan to adjust the rig before each race, track the number or turns you add or subtract and write it down in a logbook. That way you always know how your rig is set and over time, can learn what works best for your sails. On the other hand if your racing conditions are consistent or you just don't want to fiddle with the rig every week (or every race), don't be afraid to find something that works, set it, and forget it.
