Would it all be painless? Do you know which one would be the best in terms of painlessness, effectiveness, time until death, and pleasure? I know that's a lot to ask
I'm just going to answer the questions based solely on heroin. Even though others would be more effective, I have reasons that I'll try to cover later.
1. Would it all be painless?
This is not an easy question because there's not enough information.. would 'it'.. what is 'it' to you? If I assume 'it' to be an overdose on heroin, then basically yes. The yes assumes you use enough to die. If you use enough to throw up in your lungs and then don't die, or you use enough to die and throw up in your lungs and are prevented by others that 'save' you, or something else that keeps you alive.. then no. Overdosing on heroin will basically be like A) Stick needle in vein B) Inject drugs in vein C) 5 seconds pass, you feel fucking great, 10 more seconds pass, you pass out. - There is no pain unless you wanna bitch about using a 0.2-0.3mm needle. If you die during this, you will no be aware. So no pain. If you are resuscitated, then you could have pain from things caused by the heroin overdose (e.g. throwing up in lungs) or being intubated in a hospital to save you.
2. Best in terms of painlessness?
This is not really possible to answer.. for me at least.. opioids relieve pain..
3. Best effectiveness? I like car analogies, so lemme say this imagine you are gonna light yourself on fire, this is asking which octane to use. Unless you try to find a bad opiod to overdose with, say suboxone or buprenorphine+nalaxone, it most likely won't matter, just use enough.
This is difficult because I haven't tried a lot and I don't know a lot about the specifics. Heroin works great. Fentanyl is apparently more effective. Then you have the fentanyl that's been modified like carfentanyl and fufentanyl (probs misspelled these). If you can get heroin, choose heroin. If you can get fentanyl, choose fentanyl.
4. Time until death?
Shit, I don't know this one to be honest. I overdosed on heroin+alcohol, found 4 and a half hours later. 'Should' have died according to others, but I didn't. Then overdosed on heroin+ketamine, found 7 hours later, so much more severe of an attempt.. Didn't die. But then you have people overdosing and dying quickly, on accident!! So I don't know. I would recommend combining heroin with another method, not another drug! I mean like heroin + bathtub of water. Or heroin + partial hanging. This way it should be quick and painless.
5. Pleasure?
Heroin feels fucking great. But if you use heroin before attempting, you're basically helping yourself not die. You have less heroin than you first did. You have more of a tolerance, needing even more heroin. If you do heroin and then try to die, assuming you used more than one time, pretend you're attempting suicide by gunshot, with a bb gun. Just don't do it. But if you mean overdosing and pleasure, well, you may have 5 seconds of pleasure like I stated, then pass out very soon, so you won't get to experience the pleasure.. You won't remember it at all if you are alive later. So basically, the pleasure is only there if you are alive..
I hope I answered your questions well. If you do this method, do it with another method like a bathtub with water or hanging. Only use intraveniously for suicide.. If you have anymore qustions, feel free to ask away.