Agree Jonny - however I think different strategies suit different players. I tried three times at max allies around L80 with 80k defence (mixture of HP and Hydras). Got hit every time, most allied, but it was taking forever. So I dropped the ally count gradually, checking the BL to see what the stats were like until I settled on 72 allies. As I stated earlier, Only 200 and below could see me and my stats from event mobs was sufficient to go through the run without a loss. The pickings also seem a bit broader at the lower ally levels, perhaps because there are less active players in the BL.
So I think the thing to do is assess your relative strength at your level and choose a strategy that will work for you. You may need to try a couple of different things until you find the right one. And don't try to go for it during a PvP quest!