A slight update to the win-up, since i posted this I've actually got 3 epic chest in the Poet's Palace with a group of 52s ( killing >60 ) . None of which had a reactant in them so it was a cheezy win-up.
it's the only place I've got an epic chest by killing over my level range. I've gone to other places like the Ancient Table and that mesa area via pillars of flame and got crap for having bothered to go there.