Update:
I have all the resources.
200 mg Oxicodone (Extended-Release)
44 mg Alprazolam (Xanax)
150 mL booze at 35% alcohol by volume
Bismuth Subsalicylate (Pepto Bismol)
Grapefruit juice
My suicide note will either be on my desk or by my bed to be seen the next day while I'm "sleeping".
I started drinking the juice yesterday. I'm gonna increase the amount I drink each day next week.
My CTB date, I'll either fast or eat bland foods that help reduce the chance of vomiting (I still need to do more research on which would be better). I'll drink a glass of grapefruit juice in the morning and take Pepto Bismol probably every six hours or so, starting when I first get up, to coat my stomach.
At night, when I start to get tired, I'm gonna take my last dose of Pepto Bismol along with 2mg of Xanax to start sedating me and easing my nerves. I'll take a bit more Xanax as needed if I don't really feel the effects as much as I want to. Around the 40 minute mark after taking the Pepto, if I find that my SI is calmed enough and I'm relatively close to falling asleep, I'll take all the Oxy and the rest of the Xanax, using grapefruit juice to wash them down. If the Xanax is sedating me before that 40 minute mark, I'll take everything then.
(Because the Oxycodone is ER, it's twice as likely to have dangerous effects. It'll also mean that the side effects will take longer to kick in than IR. Hopefully, the Xanax will have knocked me out by the time the Oxy starts working.)
I'll then send a personalized suicide note to my former friend. As they go to bed early and I go to bed late, I'm not worried about them seeing the message soon and being able to stop me. If they do see the message before morning, they don't have my address, so I'm not worried about them sending the cops. Hopefully, they won't see the note until morning. Hopefully they won't really care. I treated them like crap so they wouldn't...
After I send them their personal note, I'll try to drink as much alcohol as I can. As I don't drink, I'm not sure I can get much down, but I should have enough Oxy to be lethal on its own. The added Xanax should ensure it. The alcohol is overkill. I'll use the rest of the grapefruit juice as a chaser. If I begin to feel nauseous before I finish the booze, I'll stop drinking it. I'll then try to go to sleep. 3 downers in my system shouldn't make that too difficult.
I'm gonna lay on my back so that if I vomit in my sleep, I'm more likely to asphyxiate on it and it'll fill my lungs. If all goes well, I'll catch my bus from either asphyxiation or respiratory depression.
If I find the Xans aren't working like they're meant to before I take the Oxy, I can back out with little repercussions and no one around me to know of the started attempt. I'll just sleep really well that night.
If the plan gets messed up after I take all of the drugs, I'll get hospitalized and then play it by ear after that, I guess. Hopefully I've planned enough to make sure that doesn't happen.