I tested this out last night and it looks like you can run both at the same time. Basically doubles spell crit.
Anyone running with this and played with it extensively?
Hate to give up a slot -(maybe loose cleanse/purge or a snare), but my crit went from 20 to over 40, not sure if the fireballs proc or not.
Don't think I saw them fire off.
Also, just reached fighters guild 10. With dawnbreaker are you using it as a finisher or opener?
The cast time seems a bit wonky and if you are in combat or snared it seems it won't proc reliably or maybe it is just the awesome lag we have.
So are you finding you are saving it or because of how it operates- trying to open with it then snare/talons/petrify, lash etc fire if off again if you can or do you finish with it? I found a V14 on a horse reading his map, fired off dawnbreaker, than a talon/lash and he was done - mucho fun!
The other ULT I have is dragons leap but I am wondering if I should go back to corrosive. We need 3 ULT! :-)