Ideally, I would order a 10cc sterile vial online. Most of the sites that you purchase pins through will have them. They are only $2 or so. With that, you can add 10cc of bac water, making each 1cc of solution, 1000iu. At that ratio, 25 clicks on the insulin pin will be 250iu. That gives you a lot of liquid to measure, making the measurement easier to do. You can use 2cc of bac. It'll just be a small measurement. If you were to add 2cc of bac water to 10,000iu. Every 5 clicks on the insulin pin will be 250IU. If you use 2cc water, I would go with a 1/2cc insulin syringe,(and always a 1/2in needle) because the 1/2cc barrel will be easier to use, drawing only 5 clicks at a time. The 1cc insuiln syringe is numbered in increments of 10, making it a little harder to measure out 5 clicks