Nitrogen sounds like the better option out of the two if you are willing to jump through all the hoops of getting the right equipment and setting it up. But it might be a little difficult to do so.
Otherwise, if you can access SN and all the other meds, then I'd suggest you look into whether or not you can find methylene blue as well. This would essentially mean that you wouldn't have to call EMS in case you throw up or your SI kicks in. You could just self-administer the antidote but this requires learning how to inject it safely. Although, all the other side-effects that come with SN like tachycardia or nausea will still be there, so I wouldn't say it'll be fully comfortable. You'd just have an additional safety net is all.