On my Beneteau 31, you don't need that much tension on it. I usually just hang onto it with my left hand.
Your setup may be different, but the most important thing on mine is to keep the boom at the right level. It works best if I let it float and find it's on position, i.e. let off some on the sheet and vang prior to furling. This seems much more important than outhaul tension.
s/v Dancing Days
Lewisville Lake, TX