Im not sure your understanding of stat weights are correct.
If you go to the website (or use reforgelite) and do this
Mastery - 2.7
Haste - 2.4
Int - 1
Mastery - 0.7
Haste - 0.3
Crit - 0.2
It will still reforge your gear the same, you just set the highest number to whatever stat you want, in saying this it really is just down to preference, get your haste / crit where you want it and dump everything you can into mastery, Its almost impossible to give you the exact numbers of the stat weights for this encounter (to my knowledge anyway) because it can be played differently from group to group or even pull to pull.
Also if your on 210k dps then there is no issue.