After auto-calibration, you definetely do not want to be at -12. Change the gain on the Sub to be within the range of the auto-calibration (-12 is saturated level). once you get something closer to zero after the auto calibration, then let your ear decide if you need to increase it. I go 3dB up after auto calibration for example.

2 M80v3, VP160v3, 4 QS8v2, HSU VTF3-MK4
Integra DTR-70.2
Panasonic PT-AE2000U 120in screen