That is assuming the system is dry and empty (been flushed and blown out).
5 ounces in the compressor sump, you fill it through the hole on the bottom of the compressor. 3-4 ounces in the evaporator, some in the R/D and the rest in the condenser.
You really might want to reconsider that POA eliminator. The POA valve is the heart of that system and new/good used ones are easy to find.