So, I'm not certain of how the numbers stack, but here is the poison mechanic as I understand it:
FACTS
From the time you first apply poison with any ovipositor attack, the opponent will take DoT for 5 ticks (looks to be 1/second).
Once the 5th tick happens, the opponent takes no more poison damage until additional poison attacks are made.
SUPPOSITION
If you only apply one poison attack, it seems to be 0.3% * 5 ticks (1.5% total).
Now, here is where it gets interesting, if you apply more, the duration DOES NOT increase, but the damage does - for example, spamming d3, I have gotten the last tick to hit for almost 20%.
I think that the amount of poison damage for an attack is set (I think some are 1.5% and some may be 2%), and that damage will be dealt regardless, so if there is one tick remaining and you hit with another d3, the last tick will be increased by the full poison damage amount (1.5%). This is how you get some seriously huge ticks on the last 1 or 2.
Of course, this could probably be figured out in the lab, and more discussion has been done in the venomous general thread I think.
So, the above, and the restand, and the different play-style from SQ. SQ is like, agro pressure, Venemous is more like, annoying/patient pressure