Anti-emetics happen to be my area of expertise, I'm not a doctor but I have a science background and I've co-written a book on nausea and vomiting, with another (more general) one due to be published later in the year (hopefully before I CTB, the publisher will withhold royalties otherwise). I wouldn't want to weigh in specifically on SN without doing some research though as it's not a method I'm overly familiar with. At a cursory glance, I agree with autumnal's assessment.
I'm also hesitant to repeat much of the discussion in the threat autumnal linked to, the technical discussion can become very confusing, very quickly - and even among experts, there is sometimes disagreement as to the effectiveness of one medication over another.
Metoclopramide is generally considered the best anti-emetic for the job (for reasons discussed above) and perhaps, more importantly, it is tried and tested. I and others could easily suggest alternatives and different combinations that may theoretically have the same effect, but with that, you introduce the risk of uncertainty. If I were in your shoes then I would need to find an alternative as I'm one of the minority who suffers extrapyramidal side-effects from Metoclopramide even at a fairly low dose, but if you have no such trouble it's worth the effort of sourcing, or using an alternative dopamine D2 antagonist (domperidone may be a good fit as it also has some prokinetic properties).
Edit: Corrected a couple of typos.
