ok, first you want to be sure that you are using bacteriostatic water, NOT sterile water. It will hold a lot longer in BA. I usually 1cc of water to a vial, depending on how I am dosing it. The more water you use, the easier it is to measure. What you want to do is use a clean insulin pin to draw up your water, then poke that pin into your gh vial and slowly trickle the water down the side of the glass. Dont shoot it straight on the puck, as this can damage the hormone. after you have done this, be very gentle and slowly swirl the vial, as the puck disolves. DO NOT shake it. Once it's disolved, its good to go. At this point, it is very fragile, so be sure to get it back in the fridge if you arent going to use it. 

From here, its just math. If your vial of gh is 10IU per vial, and you add 1cc of water, then 1cc is 10iu. If you wanted 5 iu, half as much, then you'd inject half the water, .5cc. 2.5iu would be .25cc and so on.