It comes out to be right at 6:20 from the time you drop him, until he spawns. Regardless whether you loot him or not. Standing right at -105 , 995 , facing SW , also gives you a good look at the spawn. Knocked him out 7 times before the Fabled popped. Then popped again right after.
We took him easy at level 16 and under.. We had a full group however I mainly did all the damage.. Was 16 necro. Had a shaman sow me and the rest kinda just didnt do much.. They got killed a few times ect. =p. A warrior kited it around but was easy for me to, just med kite. Didnt use pet cause he died early in fight and cost to much to get another so just kept using heat blood over and over.. Lots of resists but did the trick eventually, he doesnt regen much.