This isn't the best place to ask. Perhaps, make a new thread or comment via, https://itch.io/post/1486449.
As for buying that many gifts, do be careful on how you distribute them and which account they end up attaching to. Apparently there are cases of people applying the bundle twice to one account. Support is swapped with request at this time so if something goes wrong it might take a while till they can get back to you.
As for buying them at the same time in bulk. No idea.