Well, that was quick.
Flush with my success soloing most of Carn Dum and Urugarth at 56, I strode into the Mirror Halls at 60 feeling like Babe Ruth in a game of T-ball. Sure, this would be on-level, and I was six levels higher than the Angmar instances, but now I've got EoB, some nice 2nd-Age weapons...
20 seconds into the fight with the two matrons, and I'm toast.
I gather Angmar instances are easier than Moria instances not only because of level, but because Moria is scaled for players with LI's? Or is the Hall of Mirrors just hard to solo? Not being able to split up those matrons was brutal.
Imho, the key to this instance is to separate the 2 monsters. It's not a question of level, class or gears. It's simply the fact that if you are alone and have no permanent crowd control (like a burglar in mischief or a LM not traited in red), you are doomed.
You have to kill the matrons within 30 seconds or they get a +1000% damage buff (that isn't a typo). I've been unsuccessful in soloing water wheels, but it's certainly doable on level, mirror halls really isn't.