Nirvana ppp growers advice needed please

As above growing nirvana ppp 4 plants in a nft system the plants are 8 weeks and 3 days into flower. but 2 of them look done for the last week all pistils have turned orange pistils are recording and 90% cloudy but no amber.the buds are huge and smell like sweet bubble gum.these plants have stopped growing now just ripening off.but the other 2 plants buds are still growing and there shooting white pistils all over the place and look like they are 10 days behind.will it be ok to let the other 2 finish up or will the 2 that's done go over ripe ? This is. My 4th grow but my 1st time with this strain there in a 1 metre square scrog and under a 600 w hps light

Nothing is exact in Nature. If some are done before others, that is generally expected. But you already answered your own question really, when the trichs are half clear and half cloudy that is when to pull the plug.
Some wait longer for fuller cloudy trichs, but stopping before they turn amber.

Look at the trichs, if there is any sign of milky clouds chop away, if not let them go another 3-7 days and check again. GL with them, sounds like you did well on the grow.