just try adding points until u don't have to anymore.
I'm also going throwing next gen again. It will be a 18/18 build I think, with wpf split in two between 2h and snowflakes.
I wouldn't recommend anything less than 4-5 pt though, especially with snowflakes. PT also adds to flight speed of the weapons, and that contribute a lot to accuracy. Also, with 2pt u will glance a lot. It will work for stopping running archers however + the occasional headshot.