When drinking an infused extract of Scrying, whose knowledge of the target affects the Will save DC?

Question

When the target of a Scrying effect resists with a Will save, the DC increases or decreases based on the caster's knowledge or familiarity with the target. A psychonaut alchemist can create an extract of Scrying, which is activated as a standard action; the DC should start at 13 + their Intelligence modifier.

The infusion discovery lets this alchemist create an infused extract of Scrying extract for someone else to drink, and it functions like a potion. The rules for potions state the following:

Potions are like spells cast upon the imbiber. The character taking the potion doesn't get to make any decisions about the effect—the caster who brewed the potion has already done so. The drinker of a potion is both the effective target and the caster of the effect (though the potion indicates the caster level, the drinker still controls the effect).

Suppose the alchemist has only secondhand knowledge of a creature, but the alchemist's friend knows this creature very well. The alchemist then prepares an infused extract of Scrying to target this creature, and this friend drinks it. Does the Will save DC increase because the drinker is familiar with the targeted creature, or does the DC decrease because the alchemist is unfamiliar?

Answer 1

Based on

...The drinker of a potion is both the effective target and the caster of the effect

The imbiber's knowledge would be what determines the DC, in your case, increasing the Will Save.

---

Other references:

Infusion (Discovery) doesn't indicate in change in how Extracts work.

Alchemist Alchemy indicates that the potion rule applies, because the only cited difference from potions is that all levels of Extracts take the form of a pseudo-potion:

Extracts are the most varied of the three. In many ways, they behave like spells in potion form (...) (u)nlike potions, though, extracts can have powerful effects and duplicate spells that a potion normally could not.

Answer 2

Whoever drinks the potion is the effective caster

The character drinking the potion is not making any decision about how the spell will behave, nor he will change any of the spell variables, he simply has a higher chance of succeeding.

What causes the confusion is this part:

The drinker of a potion is both the effective target and the caster of the effect (though the potion indicates the caster level, the drinker still controls the effect).

That makes little sense, and any potion that contains a spell that can target a creature, would target the drinker if we take that wording literal, and thus, would make inviable to create potions of any spells that should target another creature. It also says the opposite of what was just said about who controls the effect.

But what does this mean is: Whoever drinks the potion does not make decisions that would affect the spell's variables based on caster level or character stats, like the duration, save DC or range of effect. Those were already defined by the creator.

In other words, if there is a decision to be made before casting the spell, those decisions are made by the creator. Otherwise, those decisions are made by the drinker, who is the effective caster.