I can't remember a thread about which canoe to rent or buy that hasn't recommended that you try out the ones you are considering before you decide. When it comes to canoes, "tippy" is about as useful a description as "sexy" is about a man or a woman. To each his own.
What I do know is that weight matters, at least for most of us average blokes heading out into the Park interior. Consider this, the typical male stride is approximately .75m. You said there is a 9 lb. difference between the Elite and the Prospector. If you don't see a meaningful difference in your experience test paddling the two canoes, then you would be carrying 9 lbs more with each stride you take carrying the Prospector. 9 lbs. more on each stride over a 1000m portage, means that when you carry the Prospector your legs have to carry 6750 lbs more over a 1000m portage. Whew!
Perhaps the the actuaries on the site will find fault with my logic, but I suspect, when push comes to shove, you will have more fun carrying lighter gear if it otherwise serves you well.
Mark S.
http://www.ABRweb.ca .. Algonquin Backcountry Recreationalists - Caring for Algonquin's Backcountry