In my experience with fungi I've never had to deal with nausea. Everyone is different, but if you do feel unwell ginger ale is always a great remedy. I had my first mesc journey a couple of months ago with peyote and peruvian torch and when the nausea hit all I did was sip on some GA and within a couple of hours I was golden.
I have never taken pure ginger though. No help on dosage here, sorry. Maybe take a bit by bit until your pukiness eases.