I'm sorry Pattie. I don't know ProZinc, but you could post in that insulin specific forum for advise.
We usually don't recommend shooting below 150 or 200, unless you have lots of data (numbers to refer back to).
But, she may go up above that no shoot number in a half hour or so, and then maybe you can shoot your insulin. If you did, you would have to be around to monitor and to do spot checks through out the day.
I would check with the people who know ProZinc insulin, and see what they have to say.