Well you couldn't ask for more now. Just be patient and hopefully the fluid will start going down. I sent your post to Iain Utah hopefully she'll come and talk to you since she had this in one of hers.
Good advise too, I know just recently Iain Utah hatched a Toulouse baby that had a lot of fluid in it's head and it's doing real good now, so give the baby time hopefully the fluid will absorb and it will be a normal gosling.