I think you can safely argue without playtesting that all the stuff with double or triple Potions does not work.
Just take County as an example. Why would you ever spend 4 Coins and 2 Potions on something that is weaker than Vineyard (mostly is) while costing far more?
The opportunity costs of getting 2 Potions (or M-Medicine) and the matching risk (have people who suggest such doubble Potion nonense never played with Treasure Map?) is simply far too huge for the payoff.