from what I have experienced, castaic is similar to piru with wind. pyramid has some islands out there that protect some of the water, but you do have a ton of jet skiiers up there. basically, you need to make sure you are on the water at sunrise to get any decent water around here. even then, you are not guaranteed anything. your best bet would be to get a ski cove membership at castaic. I have been pushing the people at piru about this, but they dont want to do any extra work.
let me know if you ever need a third.