Hi.
I'm testing a similar deck. Not identical, but very similar.
I play only 4 Duress. Not thoughtsize. Why? Without gush, flash or merchant, the more important disruption will be in table, not in hand. You only have to worry about FoW, and, without brainstorm, it will be more difficult find them in 1-3 turns. And why duress, and not Thoughtsize? Because i use Spoils of the vault. In a deck with so many 4of, its safe to tutor for something without lose. And they have great synergy with top tutors.
Thanks
