Instead of putting 5ml of BW to mix the HCG, just put 2ml of BW directly into the HCG vial. At 5000iu/2ml you will have a concentration of 2500iu/ml. All you have to do is draw out .1ml (10 ticks on an insulin syringe) and you'll have 250iu of HCG. Then you don't have to have another item to stock.