Yeah should be much better with a properly working smaller motor.. Talking about the foam board options, just wanted to mention, in case you didn't know already, Great Hobbies is Flite Tests Canadian Distributor and they have a location in Mississauga. They carry most flite test products including power packs as well as their water resistant foam board. Haven't gone there yet but plan to especially for the WR foam and their special glue sticks.
Also, just from my experience. If you plan on doing any morning flying, the morning dew will kill your plane. Not sure if you've seen the minwax polyurethane video but that has helped a lot.