It can only be set to windowed after it is registered. Maybe setting byte 24 (yes, that's a hexadecimal address) of gish.cfg to 0 helps, but I don't think it will make the situation any better if you don't have an old file to base it on. I can post a 'clean' gish.cfg (as Gish creates it when it doesn't find anything) modified to run in a small window if all else fails.