For every 1,000 iu's of hcg, I use 1cc of water, so, in the case of a 2,000 iu hcg you would use 2 cc's of water total.
Then when injecting the following formula is used:
125 iu's = 12.5 units on insulin syringe
150 iu's = 15 units on insulin syringe
175 iu's = 17.5 units on insulin syringe
200 iu's = 20 units on insulin syringe
250 iu's = 25 units on insulin syringe