Depends on how many fina cartridges you have. If you have 1 cartridge you need the 2G kit, if you have 2 cartridges you need the 4G kit. It's just a matter of condensing multiple cartridges into one batch.
Does that answer your question?
PNP has good Liquidex prices. I hope you don't intend on running the Liquidex with the Fina, as it will do no good. Fina can produce progesterone related side effects, very rare. In that case you would want Winny, which naturally inhibits the progesterone related side effects.