I'm not sure where to set the crossover for my RTi8s. I have a Hsu Research VTF-2 subwoofer (CSi5 center, CSi3 back, and RTi6 surrounds). My Marantz SR7300 lets me choose between 80 Hz, 100 Hz, 120 Hz. I've set all of the speakers to "small" in the Marantz set-up. Which crossover would you guys suggest for the RTi8s with the VTF-2?