Hello, 

I have a cake order for a 3 tier cake, the bottom 12" tier is the only real one and the others are dummies. With that being said, the middle tier is going to be a ABC coated caked and then some gold "edible" glitter (sugar) will be added and the top tier is just a coated in ABC but then some gold drips will be added. How far in advance do you recommend making these fake tiers?

Also, do you have a method for adding the glitters to the cake, should i add it to the buttercream while its still "not set" or should I let it crust hard and then add pipping get to it? 

Any advice is appreciated.

I would think about a week ahead should be good otherwise there might be some change in color—since you are dealing with gold    I have made b’cream cakes for display in my bakery that lasted a year before they were needing to be redone  but you need them to remain exactly the same as the “new” real cake so don’t take a big chance of having to redo them

Thank you very much @Kakeladi. 

I will start a week in advance. Also do you have any experience with adding pipping gel to a ABC frosted cake? Any tips?

I have done it very occasionally.........what is the reason you think it's needed?

.