I think you should figure out when you can get her pd done when she hasn't just eaten, because I think you need to wait 1-2 hours after eating when they are that little to prevent reflux issues (which most CFers seem to have). In my experience, evenings would be better, because you might get her used to it and have it help her fall asleep eventually. BUT, if she is developing any lung gunk, early in the day might be better, because it would move around anything that might have settled through the night.