I would run them for 1-4 hours (at max) break at random, and start all over 1-4 hours. Total of 12-14, like Lil said, and just be close by hitting (r) to see if you get whispered from time to time. If I do get posted and I'm afk, I hit them up with a "sorry guild chat is crazy today" and answer any question they had. Or you could say, "talking to 3 people sorry" and then ask what they need. It's worked for me. The key is to mix it up and try not to run them like a machine. Stop at random or just find some place to afk for a bit, then start back up. I sometimes port to a city and afk for about 5-6min then hit start again.