Alchemy Formula 1 Poison

So I need to fix my rules on this as a player doing alchemy

once you have alchemy you can test potions for a general idea with a test kit or lab

Then you open trees of specialisations like incendiary, black powder, acid, apothacary

I may do herbalist also - maybe even other skills could use this

Formula are researched like wizard spells and you can fail to comprehend them and be unable to use them. Formula can be found and swapped you can get one per leVel To a max of the relevant stat

You can find or develop others these are examples and in same cases can be combined which stacks the cost and difficulty to make a bit.

This is a skill - one of many
You get a formula per level
you can memorise a number of formulas up to the relevant attribute max
You can record formulas in books 

You can invent more - try mixing some of the effects

Each tier level needs ingredients = tier number +1
0 = Common in yard, cottage, gardens, patches of woods or in soil, find 1 per hour or 1cp
l = Uncommon, found in town or a terrain type, find 1 per day or 1sp
2 = Rare, hard to find or create or foreign, find 1 per week at 1gp
3 = Very rare, find 1 per month 10gp
4 = Very very rare, find 1 per 3 months 100gp

5 = Unique, dangerous to acquire or limited material created in past or one tree, find 1 per year 1000gp

You could find ingredients or keep ingredients as a single box and just record their cash value the user can subtract from. 1 ENC per Tier.

First Aid can help a person stay alive an extra round per skill roll
Herbalism basics include +1 on a save antidote usually a plant based paste
Apothacary basics include +1 on a save antidote usually a mineral based pill or tonic
Healers can help the patient get an additional save with a round of treatment
Healer can keep a patient alive

Mandrake, mistletoe, animal or monster venom or blood, minerals are common

Require a stove to make and some containers and utensils at least
Half skill with a camp fire
Kitchen and stove is normal
Alchemy lab will offer bonuses = to lab rating +1 to +3
- basic lab could be carried in chest less fragile x2 cost
- basic lab fits on a table top 10 ENC 100gp +1
- advanced lab fill a room 100 ENC 1000gp +2
- custom built lab fils several rooms or tower floor 1000 ENC 10000gp +3

cumulative = poison attacks of same type add
noncumulative = only one lot of poison damage in one encounter

Tier 0 = Lv Zero
1 Blade Bite - venom +1 damage or non with save, ten-minute delay, non-cumulative only one save per fight 

2 Sting Salve - antidote +1 HP heal vs poison, apply direct vs venom, eat vs ingested, non-cumulative

3 Ratbane - Ingested d3 damage or none if save, one hour delay after eating 

4 Identify - know type of poison from a sample with a test kit or lab 

Tier 1 = Lv1-4
1 Venom - venom d4 damage or 1 if saved ten-minute delay

2 Enfeeblement - venom -d3 damage to one attribute (each a separate formula) if sail a save. d4 rounds onset time, each hour one point recovers

3 Poison - Ingested d6 damage half if save one hour after eating

4 Onset - can make formulas with longer delayed effects or work instantly

Tier 2 = Lv5-8

1 Bloodbane - venom damages 1hp a round, stops when succeeds in a save

2 Sleep - make a tier 1 or better poison cause sleep, lasts 1 hour

3 Contact - damage by touch to make items dangerous to the touch, hour delay (if sped up with onset formula then the contact poison burns on touch and is obvious)

4 Refine - double damage of another formula

Tier 3 = Lv9-12
1 Blind - make a tier 1 or better poison cause blindness instead of 2d4 rounds

2 Gas - make a tier 1 or better poison gas 1 range circle 

3 Antidote - counter one specific poison if you identify the formula or heal d6 poison damage

4 Combination - make multi-part poisons requiring all parts to be consumed to activate, parts can be different types, hour onset and save after one hour

Tier 4 = Lv13-16
1 Bane - one species per formula +2d6 damage and -2 save

2 Boiling Blood - venom damages d6 a round, stops when succeeds in a save

3 Paralasys - make a tier 1 or better poison cause paralysis 2d4 rounds 

4 Black Blood - save or unconscious in a d4 rounds with zero HP and losing 1HP per round until revived with fist aid or healing or magic neutralises poison

Tier 5 = Lv17-20
1 Petrify - save or over a d4 rounds turn to stone

2 Liquify - save or flesh turns to a liquid mess with a skeleton in it

3 Deadwalk - make a tier 1 or better poison to cause the target to arise as a zombie if they die as a side effect

4 Long Sleep - make a tier 1 or better poison put the target to sleep, and get a saving throw per day to end