Increase the dose slowly till you get to 10IU. Once on 10IU there is no need to take anymore. An effective Insulin dose would be 7 to 10IU daily. Once you have used 10IU. a few times and are confident with that dose then you should be able to start on 10IU every time you use insulin.
Most users will use insulin 4 weeks ON/OFF. Using insulin this way has proven to deliver maximum benefits and minimum side effects. I have experimented using insulin all sorts of different ways but the 4 ON/OFF protocol is definitely my favorite. When using insulin, I usually start on about 5IU and if everything goes well I will increase the dose by 1IU at my next training session which is usually the next day, and just keep on repeating that method till you get to 10IU. Once on 10IU stay on that dose till end of cycle. Once you are confident with insulin, next time you use it (after the 4 weeks OFF) you may start on 10IU right away.
Note: No matter what you use, if the dose becomes too much side effects wise, simply lower the dose.