RE: Cock vane up or down?
He is shooting a drop away rest and no it does not matter which way they are oriented. Just make sure that all are passing though with our touching the rest.
It's called a cock fletch because before there was plastic vanes fletchings were all made from feathers. The feathers are called cock and hen because a male bird is a cock and a female bird is a hen. A single cock has a harem of hens. Thus one cock feather and multiple hen feathers.