I was getting off track a little too and I find I am learning a lot from other people’s questions/responses as well.
There’s no need to snack. More ADA nonsense.
The 500 Rule still does not work for her (you divide 500 by your Total Daily Dose) and this should give you the Insulin to Carb ratio. It can give you a general ball park idea, though. Her TDD lately is 48 units. 500 divided by 48 would give you an insulin to carb ratio of roughly 10.5. Her ICR is 1 to 7 breakfast; 1 to 8 lunch and dinner. That rule used to be way, way off when she was younger and espeically when first diagnosed. It may give you a very general figure to start from. Though, since you are doing well at 1 to 15, if your basals are good, then just go up to 1 to 16 and see what happens.