First of all, I've been sort of out of sorts since 5.2 launched. Entirely my fault for not putting forth the effort to learn the other two specs before the patch.
Second of all, I'm feeling a bit overwhelmed trying to learn destruction. I've spent far more time digging around trying to find numbers as roughly exact for Destruction as there were for Affliction (i.e. haste breakpoints at 6637, 9778 etc, then stack mastery). Tried gemming the way that the guide here says (+160 int in reds/prismatics, int/haste or int/mastery in yellows, int/hit in blues).
Long story short, (and links to rele