By Leviathan.Korialstrasz 2010-12-24 18:17:10
Highest I've done so far is over 1400 (with DB) with Ebon Hoof and Dragon Rider. Since I got my 3rd atma I haven't tried with those 2 + Impregnable Tower. Really no point though really unless you just wanna see gigantic HB numbers at the expense of taking forever to kill the mob.
As for using empathy for the HP bonus, I haven't tried it but I'd imagine you can. Wouldn't be hard to test either, merits aren't exactly hard to come by these days.