you are thinking in the right direction. i wouldn't get too concerned with mashing out unless you are looking to add a point or two to your efficiency. i batch sparge as well and will sometimes use a given amount of the sparge water to boil up and add first to reach mash-out temp for 10 minutes, or so. then, vorlaugh, drain, and finally add the rest of the sparge water. I hope that denny sees this post and chimes in, as he is the godfather of batch sparging and usually is quick to reply on this topic. hope that helps, or at least adds to the discussion.