Gauge 22 resistance is about 0.016 ohm/ft. Your cable is 8 ft making it 8ft + 8ft =16ft. 16 x 0.016 ohm = 0.26ohm. Assuming 4ohm speaker it will make 4/(4+0.26) = 0.94. It means about 6% voltage drop resulting in about 12% power loss. This power loss is equivalent to about 3.5% in perceived loudness change. For gauge 16 cable perceived loudness drop will be 0.9%
On the other hand while 16ft of gauge 16 is 0.064ohm inductor in series with the woofer is at least 0.1 ohm.
Gauge 18 copper wire at 20kHz has still 100% skin depth, but thicker wire has slightly lower inductance. I don't see reason going below gauge 12, but Acoustic Zen does. My AZ Satori Shotgun has overall gauge 6. It is divided into multiple isolated strands. I suspect they wan't to avoid skin effect, but why gauge 6 (0.004 ohm/ft)? Perhaps they want to lower inductance. Gauge 6 wire has reactance of about 0.9 ohm at 20kHz, 1ohm for 16 gauge - only 10% difference but it plays some role.
On the other hand while 16ft of gauge 16 is 0.064ohm inductor in series with the woofer is at least 0.1 ohm.
Gauge 18 copper wire at 20kHz has still 100% skin depth, but thicker wire has slightly lower inductance. I don't see reason going below gauge 12, but Acoustic Zen does. My AZ Satori Shotgun has overall gauge 6. It is divided into multiple isolated strands. I suspect they wan't to avoid skin effect, but why gauge 6 (0.004 ohm/ft)? Perhaps they want to lower inductance. Gauge 6 wire has reactance of about 0.9 ohm at 20kHz, 1ohm for 16 gauge - only 10% difference but it plays some role.