Walt Schroeder told me once that thrust settings are not affected by engine size or power. If they need a thrust adjustment then they'll need it for any engine. I don't know if that's true or not, but he knows a lot more about it than I do.
But the way to find out if it's right or not is to get a trim chart and go through all the tests. You can guess all day about whatever, but if you go through the different maneuvers you will know for sure if the plane needs a thrust adjustment or a different trim adjustment. One comes in some of the Futaba manuals and may be available on their website. I think the aircraft proving grounds has a trim chart as well. If not, just do a google search for radio control airplane trim chart and you'll find one.
http://www.geistware.com/rcmodeling/index.htm