I will be making my first rice paper feather wedding cake and don't know where to start, I also want to know how long it will take before it droops.
Can you give more information? If you are putting the wafer paper feathers on fondant, I don't see a drooping problem. Don't know about butter cream cause the paper is going to react to any moisture.
I will be using rice paper on fondant.
If this is the look you are going for, scroll down into the comments and she tells you how she did it. I have attached feathers to fondant with royal icing also. It doesn't take much to have them stick.