What if you want to do some funky off-time stuff on the hats, or say close them on an "and" in the beat.... Do you change your time center to another limb, or imagine the chick of the hats where they "should" be?
Maybe I can try to explain?
When I do accents with sharp opening of the HH, smooth opening with the hands or "chicks" with the foot, my left foot stays in constent motion, generally 8th notes, but very supple, then I lift the foot while in motion to get the desired effects/patterns on the HH, sometimes with a "rocking" motion as well. I only keep the foot steady when I use the HH half open for that washy sound. When the tempo is very fast, I switch to quarter notes but apply the same methods.