So are there any tricks when trying to pick a 66% het out off the clutch?
I suppose you mean trying to pick out which one(s) actually are het out of a bunch of 66% phets?
There are some markers, but none of them are sure things, otherwise it would not be considered a recessive gene. Het pieds can have a belly marker, het lavender albinos can have a sort of glow, het hypos sometimes have a slightly faded head or a head marking... or at least so I've heard. There are probably others too.