Just an update for you combat specs:
Use Wound Poison on your fastest weapon and Deadly on the other. Without the poison application talents and non-envenoming, IP is actually the worst of the poisons in terms of damage. The instant from the Wound Poison (50% proc instead of the 30% IP proc) will net you more damage.
If you need solid proof, feel free to use this spreadsheet (warning, it's not very 'user friendly', but easy enough to figure out):
http://elitistjerks.com/f31/t27244-rogue_roguecraft_spreadsheet/