Got Scorpio predicted today (again - I guess (s)he likes me), so I thought I'd give it a try with PDials after reading the debate above. Well, surprise, surprise; (s)he drawed 2 Purifies throughout the game, and used both for getting rid of his own Poison counters. You could say that I was unlucky, as (s)he has exactly 2 copies in 108 cards. However, the game ended with 19 Poison counters on Scorpio, 4 cards left for me and an EM, with 2 cards spun.
This alone proves it again that this strategy is working a *lot* better with more than 30 cards. You just have to keep one Deadly Poison in your hand at all times, Arsenic can easily take care of the rest - if you have still the possibility to stall of course; and that's where the 30+ cards come in. Also, if you fear that (s)he Purifies you, that'd also mean (s)he will negate a great portion of its damage output, just try to keep your HP on a healthy level when you Sacrifice.
Quite an easy target most of the time, despite having the perfect counter card.