I emailed Gisela again today, since she seemed to be somewhat helpful yesterday. Unfortunately, she was very brief today. I imagine she gets a lot of e-mails from other would-be applicants as well, so I'll just have to find as much info as I can on my own.
"So far we have not had complaints from former assistants in the sense of not being able to cope with their financial situation. Please, bear in mind that this is a grant and not a salary."