I never used APF in the CQ 160 (who has time to tune in 5 Hz steps using SHIFT or 1 Hz steps using VFO?) but here's a good tip for casual operating from Wayne N6KR:
Use Preset I and II to toggle APF On and Off more quickly. You can also set different XFILs using the Presets.
Preset takes some time to change but it may be better than pressing APF.
With APF I was able to copy many weak stations on K9AY when running. Notably KH6 and KL7, plus a few WI stations, I guess, running 5W with mobile antennas. But if it takes 1 sec to turn on APF, and an average station calls once, one cycle is lost. After a weak station repeats a few times, other stations decide to use the same frequency for RUN.
I find RIT good enough for APF, and faster.
Ignacy, NO9E