For solo pve poisons, go with whatever you like. Many go with instant on at least one weapon. For the second, there's a few options. Cripple is used a lot on pvp realms, especially in crowded areas. Deadly and wound both do damage and work with mut. Deadly breaks gouge/blind/sap, wound doesn't. In an ideal situation, deadly wins out but you never know when you'll make a bad pull, get a weird respawn in the middle of a fight, or have a random ally/horde attack you and wish you'd had access to your disorients or had cripple on. For instances/raiding, you'll either want deadly+instant if you don't think envenom can make up for the loss of poison dps or dual deadly if you do to minimize the time deadly isn't up. For pvp, it's normally cripple and either wound or mind-numbing for BGs and arenas.
For attack sequence, it's normally CS>Mut>wait for energy>KS>Mut>Mut>Evis. Since you're using opp mut for leveling, most rogues end up with the rest of the points in sub anyway. Without imp gouge, gouge wastes energy. If you do have imp gouge, you can use it if you want, but it isn't required to fill the gap btw the first mut and the KS.