As N900 seems to have a limit of around 200 packets/second it takes 6-7mins to get 50000 ivs which normally is enough. I noticed that -p0481 attacks sometimes generates dubiuos data, which is why I would love for Wifite script to dump it and append as 2-3 attacks is enough (maybe I got lucky and there was casual user in the meantime, no idea) in most cases.