Addiction DC = 10
+10 DC to halve time
Convert to SP: 50 SP/dose
To craft: d20+Craft (alchemy) * DC = how much progress in SP made over a week. /7 for daily total.
Example (take 10): 10+32*20 = 840sp/7 = 120sp/day, Swift Alchemy makes this 120sp/4 hours
So for the example, 2 doses of Potato Vodka would be created, and 2/5 of a third dose in 4 hours.