The goal here is to make the mast straight sideways and minimize sag to leeward. With diagonals eased, tighten upper shrouds. Center Mast in Boat. Make sure mast is firmly held in partners or mast step with chocks or hard rubber. Ease all diagonal shrouds to very loose.
Spray turn buckles with a rigging lubricant.
Tighten vertical shroud turnbuckles equally from side to side as much as possible with normal-size tools. Large tools or pipe extensions to tighten turnbuckles easily cause damage to threads. Once vertical shrouds are tight, make sure diagonal shrouds are just snug with excess slack removed and any S bend tuned out. Once this is accomplished, your rig is ready to tune under sail. Your mast is still relatively untuned, so caution is still advised at this stage.