I made a lid out of gumpaste and decided to cut the sides separately to give a cleaner look. One of the sides came off and I have to get it back on tonight. What will hold it best? Melted white chocolate or royal?

I'll go for chocolate

Gumpaste "glue". Dissolve 1 Tbsp gumpaste in 1 Tbsp cold water. Stir till dissolved. Using a paintbrush,glue what needs to be glued. I use this all the time to glue the centres of my flowers to the flowers.