I can tell you how big the doses were in the study which you appear to be referring to but, before Sqad blasts me for providing you with dodgy medical advice, I'll make it clear that I'm most definitely NOT suggesting that you should take such doses yourself!
Firstly, using (hopefully) trustworthy sources, here's why I think that you SHOULDN'T be taking very large doses of Vitamin C:
From the NHS website:
"Taking large amounts (more than 1,000mg per day) of vitamin C can cause:
stomach pain
diarrhoea
flatulence"
https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-c/
. . . and from the Mayo Clinic website:
"megadoses of vitamin C supplements might cause:
Diarrhea
Nausea
Vomiting
Heartburn
Abdominal cramps
Headache
Insomnia"
https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-c/faq-20058030
Now to answer your actual question though, the doses in the relevant trial were "hourly doses of 1000 mg of Vitamin C for the first 6 hours and then 3 times daily thereafter"
https://www.ncbi.nlm.nih.gov/pubmed/10543583