I wish I could answer your question, but I can't. I can only share my experiences with you. I have a very similar problem as I caanot seem to control my overnight (fasting) BG level.
I'm on Metformin and I take my last dosage with dinner. I generally do not snack after dinner, yet my morning levels are usually between 150 and 180. When I take the next dosage with breakfast my BG level tends to move into the normal range within two to three hours of eating.