I don't know that much about different types of insulin, but diabetes86 is correct...it all depends on your own body's need for the insulin. I take a sliding scale of fast acting (Humulog) at meal time and my base is 12 units...anything above 150 I add 2 units for every 50 points higher it is. So, if I check my bg before a meal and say it is 225, I add 3 extra units to the 12 base line for a total of 15 units. But, this is what I was instructed to do. You might be different. Sometimes I use too much and I go low, but sometimes I don't use enough and stay slightly high. It will also depend on what you plan to eat. It is a science to figure it out, but you need to know what foods do not affect your bg's and what foods do. I agree on keeping a log. That will tell you more as to what your body needs.