Go with ginger, it's the only one having dopamine blocking effect that's needed for SN. It's better to get it as a supplement than just eating raw ginger, this way you know exactly how much you get.
The recommendation is 1g daily (0.5-1g was studied). It's better to start a week before your date or even two weeks, it won't hurt, ginger in general is very good for your health (muscle pain, anti-inflammatory properties, indigestion, effective against the RSV virus, etc.).
I'd suggest maxing this to 2g (studied, safe) or even 3g (didn't look for studies) a day if you feel no side effects, because you'll be ingesting a poison (SN).
It also accelerates emptying of the stomach by 50%, so you almost get a meto substitute with ginger, and that's all OTC.
Gravol (Dimenhydrinate) treats motion sickness, it won't help with SN at all, this has been already mentioned on this forum.