I don't know if Best has a preferred position.
He says he played at 5/8 as a little kid.
His first year at the Knights he played second row in under 16s as a 14 year old - which was the position his father played for Manly and London, and where he saw himself playing.
His second year at the Knights he was coached by Scott Dureau in under 16s and Scott tried out players in many different positions, and got Best to play fullback because of his speed and ball skills. He had a fantastic year at fullback and was largely responsible for us winning the grandfinal. They picked him for NSW under 16s and put him on the wing.
In his 3rd year at the Knights he was supposed to be fullback in under 18s but was injured for the start of the season, so Starford Toa started at fullback and went so well that when Best was fit in about round 4 they put him in the centres for the first time. At the end of the year he toured with Australian Schoolboys and played fullback, wing and centre.
Last year he hardly gt on the field, but played centre for the Knights and was picked for NSW under 18s at fullback.
In short, he has played second row, fullback, wing and centres for the Knights, and wing, fullback and centre for NSW and Australia.