Thanks to the info on this site and others, my almost 6 weeker seems to be doing much better with a fast letdown and doesn't choke or cough as much with feeding now. I have been sticking with one breast per feeding. The supply seems to be matching her better now. However, sometimes she just eats for a short while (less than 5 minutes) and I can still feel that the breast feels full (she sometimes can empty the breast in 5 minutes, but this isn't the case for these "snack" feedings, When she eats vigorously for 5 minutes, the breast definitely feels more empty).
Should I put her back on the same breast for the next feeding, even if it's more than 2-3 hours since the last "snack" to ensure she's getting the hindmilk, or switch to the other breast?