In the big scheme of things, I am not sure it matters, however, if your stone is making a lot of foam you may want to dial back the pressure anyway. Any o2 that bubbles to the surface isnt going into solution, and is therefore wasted.
Usually I aerate for a minute or two right at the end of my chill when I am getting impatient with my immersion chiller. Then I fill the carboy and pitch the yeast once I get to the correct temp (usually a couple hours later in the summer).