Because many types of paper go under the name ‘rice paper’ (pretty much any paper that is thin and semi-transparent) it will be useful to post a close-up picture to determine what type of paper you actually have.
I’ve often heard washi (or mulberry paper) being called rice paper. It is thin, semi-transparent, soft - almost cloth-like:
If that's the kind of paper you have consider that:
- starch or gelatin is generally used to size paper
- you can also use other transparent adhesive like PVA or rabbit skin gluе (PVA is white but becomes transparent when dry)
- the less you dilute whatever you chose to use, the stiffer paper you’ll end up with
I’ve seen art stores sell pieces of handmade paper that is thin and semi-transparent, with distinct fibers (like in the image below) but unlike washi they are quite stiff. There is wide variety of textures to choose from. These might work for your project well.