Since you are playing NIN - I will have to assume PING is not an issue for you. e.g. your ping is in 90-120 range.
SKS is valuable until you reach a 2.0x GCD.
After that CRIT > DET

So mix and match the gear to give yourself the appropriate GCD, followed by the most CRIT. The damage difference between 14 DEX and 60 CRIT will be negligible.
The damage difference between a 2.0x and 2.45 GCD when leveraged is very significant over a long fight such as any raid boss.