Hey @Cristina,
Thanks for reaching out!
As you noticed already with your imports of 20-25 pages, imports of this size can take several minutes or longer. However, there isn’t really an upper limit, and so, in theory, as long as you leave the importer alone when an import is running and just let it run (i.e. you don’t exit the page and such), it should work.
One potential limitation is a response timeout from Facebook’s API itself, which we unfortunately cannot get around and don’t have control over 🙁 If this happens, your import should stop at some point, but all the events up to that point should’ve been imported fine and you should be able to take the rest of your pages and resume the import. We’ve got some code in place to try and prevent event duplicates from importing, so duplicates shouldn’t be a problem.
Does this information help at all? Let me know! 🙂 And let me know if you have any further questions or thoughts on all this.
Thank you!
George