i think that the PPeH highly overestimates the effectiveness of weed as an antiemetic. yes, it may help cancer patients with some of the discomfort associated with chemotherapy and some people with mild symptoms, but it's just too weak to use in the scenario that concern us on this forum.
many members throw up even when using metoclopramide both as a stat dose or in the regimen, and that's possibly the best drug to use as an antiemetic for this purpose.
i personally wouldn't risk it with weed, not with N and specially not with SN, i get that meto may have severe side effects and is completely not safe to use with some drugs like antipsychotics, but the risk of failing may increase.
maybe you could use both, they don't seem to have a major interaction.