I've tried both ways and mine still sucks, I think I got a dud. Mine will wait forever to kick on and by then it has to hit turbo mode to catch up.
You might have a problem. I noticed that mine always used a slow speed to adjust, increasing only when it had to but almost never went into a very high speed unless it was in 15-20 mph wind. Do you have the just ipilot or the link? If you have the link, you might try a software update.
To the original poster, another option that works sometimes is to lock it in on the heading and then dial in a prop speed that will hold your spot. Sometimes that worked better for me depending on the conditions. For the most part, I just learned to work with it. I had to sell mine when I bought a larger boat. I really miss it a lot. I knew I relied on spotlock but truly didn't realize until now, how much. Can't wait until I can afford another one.