I clean all of my glass carboys with PBW and rinse thoroughly.
I typically use Kmeta to sanitize. The current bag of SO2 I have says:
1/4 tsp per 6 gallons as an antioxidant
2 oz per 1 gallon as a rinse
To sanitize carboys, I usually squish around Kmeta, but I'm not sure how much I should be...