
They key is
to understand the activity profile
of whichever insulin we use,
to understand
how to correct highs and avoid lows, and to understand how to adjust our dose for our food, exercise, stress, illness, etc. Here is one reference that describes the activity of insulins:
http://www.medscape.com/viewarticle/449887_4
The article is written largely for professionals and aimed at Type 2s, but there are sections that make perfect sense to the rest of us!