Well I haven't been sick from drinking for many years, I guess I've built a tolerance. I'm concerned about absorption mostly - will it take longer? I don't have access to benzos so it will be the only thing that will relax me.
It will take longer but I couldn't tell you how long. You're taking Cimetidine/Ranitidine to reduce the amount of acid in your stomach. Alcohol is a bad idea as it will increase stomach acidity.
I can see the appeal of wanting to be relaxed during your attempt but is it worth decreasing the success rate? I also can't say on what scale drinking alcohol would affect this as there's too many variables.
I don't think any tolerance to alcohol will matter; more the fact SN is likely to induce vomiting on its own and with alcohol even more likely. If it's absorbing slower it's less likely you'll have absorbed a fatal dosage into the bloodstream if you throw up with alcohol vs no alcohol as an example.
At the end of the day there have probably been cases of success with the use of alcohol but I think it's in people's best interest to decrease the likeliness of having a failed attempt by any means possible. Vomiting seems to be the biggest risk along with not following an anti emetic regimen