If anyone is interested, I´ll copy the the best instructions from the site:
"
Preparations:
1) Clean the leaves/seeds.
2) Dry them.
3) Simmer the needles in water for about 30 minutes, possibly with a splash of lemon juice added to the water (in order to enhance the water's extracting performance). (Skip for seeds.)
4) Retrive the yew needles from the water and then discard the water extraction (since the liquid only contains mostly volatile oils and compounds (ephedrine) that impede the taxine and make you sick. (Skip for seeds)
5) Dry the needles in a convectional oven at 85-90 Celsius and crush them. (Skip for seeds)
6) Put the crushed needles/seeds in a jar of alcohol (80 proof minimum) and stir with a clean spoon to get rid of air bubbles.
7) Cap the jar and store in a cool/dry place, away from light, shaking daily for a minimum of 1 week to a month.
8) Strain the resulting liquid extraction, boil the alcohol out and store the liquid into a colored dropper or a clean glass jar.
9) Store it in a cool/dry, place away from light, until you're ready to use it.
Notes:
Don't use the tincture unless you're 100% sure you're ready to die. There is no antidote for the poisoning.
Antiemetics should be taken when using the tincture as a precautionary measure.
This extraction is gonna taste bitter, so it's recommended you dilute it with water and probably add some flavoring to mask the taste.
The concentration of taxine in the leaves are highest at winter (2.0%) and are lowest in the summer (0.6%). The low end of the lethal dosage is 0.5 grams of leaves for every kilogram you weigh in bodyweight. Regardless of the concentration, the recommended dosage for a real attempt is 2g/kg. The concentration in seeds are always at a constant 0.92%. So the minimum is 6 seeds (0.362g)/kg. The recommended dosage is 24 seeds (1.448g)/kg. The lethal dose of taxine is 3/mg/kg.
The shelf life will be up to around 7-10 years, though making a new batch every 3-4 years would be recommended. You can extend the shelf life of the tincture by adding a little glycerin (5-10%) in the tincture. It will help stabilize the ethanol to slow down the evaporation rate.
Taxus baccata and Taxus Cuspidata are the most toxic. Don't bother with pacific yew, they only contain minimal amounts of Taxine alkaloids.
The interval between consumption and loss of consciousness is 30 minutes. So, be sure to consume the entire extracion within the time period. The quicker the better."
Seems like a pretty great way. I just gotta find the damn tree now lol .