Just an intital note for the rest of the readers, many vails of IGF come in 1mg(1000mcg) vials. These vials will last for an entire cycle of IGF and need to be reconstituted with a diluted acitic acid. Otherwise, your IGF would break down before you have finished your cycle. Since the vials we are talking about in this question are only 100mcg per vial, Bac water will be fine.
Ok, so the question is, how much bac water should be used. I would suggest using at least 50 ticks on a 1cc insulin syringe. This way you can draw out 25iu (ticks) to get your 50mcg dose.