I am just wondering, if I invest in a bankroll, how long does it usually take to recover 2% dilution fee? I invested yesterday and I am deeply in red.
You can derive/guess from historical stats:
https://dicesites.com/bustabit although it'll massively be affected by variance (i.e. it's not unusual for someone to win or lose 100+ BTC).
But realistically if your time frame isn't measured in months or years, it's a pretty bad investment.