I think vitamin C has enough benefits that megadosing, whether for herpes or for any number of things is just plain a good idea.
find your bowel tolerance level and adjust the daily level to something you feel comfortable with considering your water intake.
for example:
consider going to 4-8 grams a day in a 1.5 liter bottle of water. My bowel tolerance tends to be at ten grams though, so this may or may not work well for everyone.