Make the shrouds snug when the mast is raked in this manner. This is your sailing mast position. If you are using a magic box put marks on the spar at the junction of the magic box wire and the jib halyard as a reference point. If you are using the ball and latch or the sharks teeth, make notes on the spar to correspond with the rake measurements given above. Make certain that when you measure rake that the mast is not bending.
Most new mains require a considerable amount of mast bend to set right.
This is a good starting point for bend. Trimming harder tightens the leech as does easing the backstay. Cut wood chocks to fit into the mast well alongside the mast so that absolutely no side bend is permitted at deck level. Tension luff only barely enough to eliminate horizontal wrinkles. Tension luff to eliminate horizontal wrinkles.