Tuning Guide:

Basic rig setup

Position mast step 490mm from the foremost keel bolt (port side)
Place a mark on the gunwhale beside the chainplates, and measuring from forestay base mark the opposite side gunwhale exactly the same.
measure and mark the center of mast collar at deck with reference to the chainplates' V1 pins.
Tension V1 just enough to lock the mast in place, leave all diagonals slack.
Hoist a metal measuring tape fixed to a slider inserted in the mast groove up to the cap shrouds height.
Center the mast sideways measuring to the two marks previously made on the gunwhales.
Center the mast in the partners with reference to the mark previously made on the collar.
With the diagonals slack, the mast should be straight enough sideways. If any side bend is present, the mast step will probably have to be moved, and the centering procedure repeated.
Once the mast is straight sideways, tension the V1 to the basic setup (19 on the tension gauge, see table below). Tension the D1 to 14, the D2 will have to be hand tight.
Prebend in this condition should be close to 50mm.
Adjust rake as follows: hoist the measuring tape fully with the main halyard and measure to the upper edge of the lower "P" band (lower mainsail luff limit). Add 2560mm to this measurement, this is your reference length. Check the distance from mainsail full hoist to the lower edge of the transom, and adjust headstay length until it matches the reference distance.