So your plan is to use a 5-6th level spell from a class you don't belong to so you can pump out a really weak decoy? Are you sure this is a good idea?
The duplicate can only cast your spells, drawing from your prepared spells for the day. At 1/4 your caster level. The duplicate doesn't get to use any of your other abilities. It can't use hexes, or consumable magic items. It also doesn't have any of your buffs, just bonuses from your equipment.
Meanwhile your body is unconscious for whatever the poison's duration is unless you have some sort of contingency that can cure that. Chances are that unconsciousness will last longer than the spell's min/level duration.
