I've just about finished up a Pharmacist class, which uses "recipes" instead of spells. (The recipes create short term use items)

However, I'm stuck on one last step regarding the poisons. For the list of poisons in the DMG, how can I best decide which "spell level" (i.e. recipe level) to assign to each posion.
For the magic items, I can use the rarity to randomly distribute them into groups based on how it feels and the chart of expected player level before receiving those magic items, but for the poisons, I'm not sure how to assign a level to a price.

Should I use the rules for creating spells, and compare the damage done by the poison? Should I go by price? Or should I go by the DC to resist the poison? If so, how? 

I've created a table to help explain my problem further? I'm not quite certain which criteria is expected to be used. Once I figure out how to do the poisons with damages, I plan on using the DCs to match poisons which only have condition affects, unless it seems worth moving up or down a level based on how many side effects it has.

![enter image description here](https://i.stack.imgur.com/i5JZb.png)