Actually 400 may not be fast enough for indoor shoots IF you're intending to use available lighting only. (i.e. flash-less photography)
I think you can buy a roll of Fuji Xtra 800 for a try or pay a little bit more ($1 per roll IIRC) to get Fuji Press 800 with finer grain like your ISO200/400 film. Some said that you get better result rating the Press 800 at ISO640. YMMV.