Wsstrange, I'm not a great sail trimmer, not a racer
, but I am a very happy cutter
sailor. In most wind
speeds and angles I agree with Ken that all three sails
are set parallel, but it depends.
What is your set up? Staysail on a boom? Adjustable sheet leads? Tell tales on all the sails?
I trim each sail to the conditions, so not just sheeting angle but also twist to have airflow smoothly on each sail. Starting with the sail closest to the wind
( foresail when beating ) trim the Yankee then see the effect it has on the staysail. Then trim the staysail ( sheeting angle and twist ) and notice the effect on the main. Then trim the main. Check that the staysail is not interfering with the slot effect from Yankee to main sail. Easing the staysail sheet or inducing more twist may be needed.
On a reach or running the twist in the staysail may need to be increased.
All that said, in practice as a cruiser not a racer
, I generally try to get a good sail trim and then I relax and don't worry about it much ...unless another sailboat approaches on a similar course...