Yeah, Slin Pins are great for SubQ injects.
I use HCG thoughout the cycle, and never for PCT. Depending on how you choose to use it, it may or may not be enough.
For a 20 week cycle, I would use 10,000iu's at 500iu/week (250iu 2X/week) to give you a reference.
If you're using it for PCT as you insinuated, I have no idea as I don't follow that school.