Bowa: in general be defensive! She will run out of arrows after some time and her mana pool will be a problem as well. Just walk and try to predestinate
her position and shoot a spear there insted of aiming directly at her. If she comes close to fight with javs its your time just stand still you should be
strong enough to tank her
I haven't dueled any amazingly geared necs on my bowa but I have gotten to duel two different ones. I never found running out of arrows to be a problem, honestly. I have pretty good aim though, that could account for it.
Also, I very rarely go in to use jab, I usually just throw them considering I have nice damage tspears with increased stack (131 quanitity), and I'm pretty good at dodging missiles.