Heritage_Head's post in Heritage series for medium room was marked as the answer
Buy two sets of heresys. Run 3 in front and have a spare (or sell it). That will voice match perfect. Using speakers from other lines won't be as good. It won't be as seamless like 3 of the same speaker would be. Cost would be about the same as well. Not that you won't like the fortes with heresys. But from experience 3 matching is the best way when at all possible.