Alright ive read alot about HCG But still have a couple questions.

So the consensus is 250iu 2x a week whole time on cycle.
If I have 5000iu I understand measuring it and dosage, but some say after 4 weeks the reconstituted HCG goes bad. At the dose mentioned above after 4 weeks I would have 1000iu left over, should I throw it away or is it okay to use the fifth week?
I've heard it can be injected IM or sub-q. What are yalls experience with this? Which do you prefer? Also what gauge needle do you use? 25g-30g?
I know you can't discuss sources but since it's not a aas where do you buy BAC water from?