I personaly dont like Rupture, especialy when it comes to bosses like Profesor and Lich King where u sometimes cant use the full potential of Rupture duo to Oozes and/or Ragings dying too fast.
On top of this i like doing Expose Armor and hate to be dependant on a Feral Druid...
As for 4 vs 5 CP Evi, i still think that on the long run with 4/5 itemisation and Ruthlessness its not worth to push for that extra point.
I used the 2set itemisation before i switched to Expose Glyph.
But again, when it comes to overall DPS, any number or tipe of finishing move u use wont matter much, since they do 6-10% of Rogues total DMG done.
Try them all and go with the one that suits u the most i guess...