Made dresser and hutch parts, 1/8" thick, Largest piece a 5x8" --need to glue all pieces together with royal icing and wondering how to tell if dry enough. I have only made thin flowers with tylose and fondant. This is gumpaste and thicker, so am a little timid...any time ranges from a non-newbie?

I would allow it at lease over night. You can tell it is dry, partly by how it sounds. if you touch it or tap it very gently, hear that it is dry-wierd explanation, but you will know.

If there is any sign of moisture of softeness, it will need more time. If you can turn the pieces over for good circulation, it can help.