When I first started, I tried all the tricks short of a separate IP for each bot.
I was running around 8 at the time each in its own VMWare, when a ban came, most if all got hit, mule safe
Tried botting with an HC barb, 4-6 hours a day all monitored, banned
Whatever DB did after the huge ban wave on dec 18, blizzard hasn't been able to detect or has not felt like dealing with it.
if you want to bot now and are ready to risk being banned when RoS comes out (could happen, would make sense). then i'd suggest going 24/7. The current bots I have have been going 24/7 since dec 18, in the last few months, i've accidentally had YAR on throughout maintenance and they're still going strong.