I got a real good deal on the 380's otherwise I would have probably went to 280's. That being said, I put them parallel to the hull halfway between the drive and the outer chine. The main reason I wanted the bigger tabs was for the ride, and the 380's make a huge difference in the rough. It takes very little tab to keep the bow down. If I was to do it again I would still do the 380's.
My boat is dead solid into the mid 80's and will be better with the hydraulic steering. The only time it chines at all is on dead smooth water and light on fuel/people.
I guess I might as well take them off though since I don't have a ext. box