[RPG] Web of the Spider Queen Executioner Optimization

I'm currently playing an assassin executioner in this season's enounters and was wondering if anyone with any knowledge of the drow (and other monsters I'll likely find in the underdark) could chime in on a question of mine. Is it worth taking the Venom Hand Master feat (ignore poison resistance and immunity)? My dailies are essentially poison attacks (one of which makes a weapon deal an extra 4 poison damage for the rest of the encounter). I know the drow like to keep spiders which probably have at least some level of poison resistance, but I don't know about what else I should expect (and thus how useful the feat will be over my other options).

This is the level up test (Currently playing at level one, but planning my feats out). I tend to focus on using my garrote for most of my attacks. Two-Weapon defense could also be retrained into something else as well. Also of note, bog heritage feat gives me +2 to nature (not a big deal) and this power:

Bog Hunter's Poison

You carefully apply to a weapon a poison that you extracted from local flora and fauna >during a rest.

Daily Poison
Minor Action Melee touch

Target: One weapon

Effect: The next attack made with the target weapon that hits before the end of the >encounter deals an extra ongoing 5 poison damage (save ends). Each Failed Saving Throw: >The ongoing damage increases by 5 (to a maximum of ongoing 20 poison damage).
Level 11: Ongoing 10 poison damage (save ends). Each Failed Saving Throw: The ongoing >damage increases by 5 (to a maximum of ongoing 25 poison damage).
Level 21: Ongoing 15 poison damage (save ends). Each Failed Saving Throw: The ongoing >damage increases by 5 (to a maximum of ongoing 30 poison damage).

====== Created Using Wizards of the Coast D&D Character Builder ======
Riddick Encoutners lvlup, level 3
Human, Assassin (Executioner)
Executioner Option: Attack Finesse (Executioner)
Assassin Guild Technique: Red Scales
Human Power Selection Option: Heroic Effort
Barovian Escapee (+2 to Stealth)
Theme: Bloodsworn
 
FINAL ABILITY SCORES
STR 12, CON 10, DEX 20, INT 10, WIS 10, CHA 12
 
STARTING ABILITY SCORES
STR 12, CON 10, DEX 18, INT 10, WIS 10, CHA 12
 
 
AC: 18 Fort: 14 Ref: 17 Will: 14
HP: 32 Surges: 7 Surge Value: 8
 
TRAINED SKILLS
Acrobatics +11, Bluff +7, Intimidate +7, Perception +6, Stealth +13, Thievery +11
 
UNTRAINED SKILLS
Arcana +1, Athletics +2, Diplomacy +2, Dungeoneering +1, Endurance +1, Heal +1, History +1, Insight +1, Nature +3, Religion +1, Streetwise +2
 
POWERS
Basic Attack: Melee Basic Attack
Basic Attack: Ranged Basic Attack
Bloodsworn Utility: Bloodied Determination
Feat Utility: Bog Hunter's Poison
Human Racial Power: Heroic Effort
Assassin Attack: Assassin's Strike
Assassin Attack: Garrote Strangle
Assassin Attack: Poisoned Dagger
Assassin Attack: Quick Lunge
Assassin Utility 2: Silent Stalker
 
FEATS
Level 1: Bogtangle Heritage
Level 1: Two-Weapon Defense
Level 1: Blindfighting Warrior
Level 2: Venom Hand Master
 
ITEMS
Bloodroot Poison
Carrion Crawler Brain Juice
Leather Armor x1
Adventurer's Kit
Ki Focus x1
Rapier
Spiked gauntlet
Dagger
Garrote
Thieves' Tools
====== End ======