Welcome - good question. I wish we knew more, but vitamin C is one of the forbidden subjects of modern medical science. Dr. Klenner, the early pioneer recommended vitamin C supplements for pregnant women, and young children. My wife's bowel tolerance increased during pregnancy and she took around 9,000 to 10,000 mg during the pregnancy. She and the baby were very healthy.
I do know that taking vitamin C is important for the mother, because nature favors the baby, even if you are low on vitamin C, it will find its to the baby, at the mother's expense, if/when you are lactating.
So taking vitamin C as ascorbic acid is not only safe, it is probably "unsafe" not to supplement. I would not worry about increased tolerance because if you don't take the C, your tissues will be deprived of it. And as far as arguments to the contrary, consider that most other species have vitamin C in their blood stream 24/7.
Owen R. Fonorow, Orthomolecular Naturopath