That's what I do also. I actually touch my chin to the cue while in my set position to verify my head is in the same place for every shot. With elevated shots, if it isn't comfortable to touch my chin to the cue, I glance down with my eyes and make sure the cue is centered between the two images I see (with each eye) of my big nose. Sometimes there are advantages to being a big-nosed Italian.I determined where my head should be for my sight picture. Next, I determined where my chin should be relative to the cue stick. I always step into the shot placing my right foot and the cue stick on the shot line with my chin in the same place for every shot (yeah right). Well at least that is what I try to do.
I know there are others who teach different techniques but I find that when my chin is in the right place relative to the cue stick my eyes calculate relative to that position.
Works for me, your mileage may vary.
For people who haven't yet found their personal "vision center" position to create the best "sight picture," they might want to check out the vision center resource page.
Regards,
Dave