Please critique my 5.2 setup please. Tried many variations and this appears to be ideal. Am I wrong?

• SYSTEM:
• Receiver: Pioneer SC-1222-K with the Class D3 amp
• L+R: Polk Monitor 75T
• C: Polk Monitor 25C
• SL+SR: Polk Monitor 35B
• Subs: (2) Polk PSW505 12" (stacked)
• CONFIG:
• L+R are bi-amped
• All speakers set to SMALL, even though L+R have (4) 6.5" speakers
• Receiver setting for subwoofer is PLUS @ 80Hz.
• Each sub is plugged into its own subwoofer preout on the receiver and LFE input on sub
• One sub phase is 0 and one is 180 (otherwise bass is much lower)
• Sub volume controls are set to 50%.

Before running the Pioneer Advanced MCACC auto calibration, I selected SYMMETRY mode, which "implements symmetric correction for each pair of left and right speakers to flatten the frequency-amplitude characteristics." That seemed like a good choice compared to "ALL CH ADJ" or "FRONT ALIGN". THX Speakers was set to NO. MCACC then told me to turn down the subs to complete the setup. After calibration was completed, I raised the subwoofer gain on the receiver to 0db and turned the volume knob on both subs back up to 50%.

This appears to be the best setup I've been able to achieve for TV, music and movies. Any advice from the pros? Anything I can do to further improve the sound?