considering that I would cut vertically
I have researched this method very well but I have since reconsidered and changed my method. To hit both the radial and ulnar arteries in your wrist you need to cut through all the tendons and nerves. You need to go very deep and even if you start off that way, research shows the cutting will get more shallow the longer the cut, which is one of the reasons it will fail. Plus, you really need to do both wrists but after you successfully cut one, that hand will no longer operate so you will not be able to cut the other arm... You will most likely survive with permanent disabilities. Exsanguination (bleeding out) is very slow and painful and is actually really hard to do... In a totally unrelated accident, I lost 4 litres of blood and almost died, but definitely didn't die... It's a lot harder than it seems.
"Several studies demonstrated that most of the wrist-cutting suicide attempts, especially for women, are not "real" suicide attempts. After a suicide attempt, the doctors / hospitals consider this a low lethality method and more of a 'cry for help' situation. There is a significantly higher chance of being locked up in the psych ward, than dying from this method.
Even with those that cut correctly,
THE MORTALITY RATE IS LESS THAN 1% (in all the studies).
Please read this study and check out the referenced studies in it too: note there are GRAPHIC PHOTOS IN IT.
https://www.researchgate.net/public...pts_by_wrist_cutting_a_retrospective_analysis
Of course, some people are successful with this method but trust me as I've researched wrist cutting very extensively, there are better, faster, less painful and more effective and reliable methods out there... And most of them are already detailed here! If you truly don't care about pain or blood etc, you'd be more successful if you stabbed yourself in the chest and neck but that's pretty hard to do and I would recommend researching other methods instead... I wish you luck with your choice.