Small and 80 Hz is a good choice for your speakers.
The AVR high pass filter applied to speaker channels set to small is typically 12 dB/octave. So the roll-off is fairly gradual and the speakers will still play into the 70's and even upper 60's before the filter has an obvious effect.
During set-up, on the PB-2000 set the gain to about 1 o'clock, the phase to 0, and the low pass filter to LFE (which disables it).
After set-up, set the speakers to small/80 Hz, and then check the subwoofer channel level. It should be in the negative range but not bottomed out at the minimum value. If you need more heat in the sub channel, bump up the channel level in the AVR a few dB (2-4 is common).