I remember seeing a thread of a dude CTBing with SN as an impulsive thing so I doubt he had the time to fast. He had stayed up for quite a while, something like 1.5 hours when most people pass out in like 10-20 minutes. I'd definitely recommend fasting if you go the SN method just because it's faster to CTB and I'm not sure if that guy just got lucky with being able to CTB or if it's normal to CTB without fasting since we don't have much info on that. Definitely wouldn't recommend alcohol with the SN. I imagine all it'd do is make you more likely to vomit and may just in general make it less likely to work through some chemical fuckery.