Which throwing weapon you use in this build?
It doesnt really matter because he has no points spend in melee classes (also 6 PS only).
But with that build I would go for heavier throwing weapons like throwing lances or heavy throwing axes to take down enemies/horses fast enough, with builds around 15 STR (5 throwing) I would go for war darts/francisca/throwing daggers because you can compensate your strengh in ranged and melee with mobility (running away/lots of ammo) and make him a hit'n run thrower
EDIT: LOL its r0ck man, the legendary stone thrower
He is using stones only, no melee weapon ever