The spawn timer on the PH seems to be about 20 mins... there is a roaming overseer that is the PH for this guy. Only camped it once through about three spawns. He was up when we got there and we pet tanked him down. Had a cleric HOTing the pets and we healed our own pets a bit as well. Don't have info on the hits or anything but is slightly slowable and dots seemed to stick. We had a 79 BL (me,) 77 Mage, 77 cleric, 65 mage (not sure on lvl here) and a 66 cleric. This was overkill, could have pet tanked him with mage and BL more than likely. He does summon and is harder than other nameds in the zone for sure. Didn't see any resists out of him between mage and I.
Timer seems to be 20-24 min can vary a bit it seems have gotten him to spawn outside of the farm at the large cog that is 1/2 in the ground... Easy solo for a 80 mage just gotta watch the enrage and pet heals... Servant and pet melee mitigation spell recommended to make this a very easy fight.