AHow much sugarpaste do I need to cover a 10" x 16" cake? (it's about 3- 3.5" deep). I've never made one this big before, and the books don't really help. I bought a big 2.5kg bag of the colour I want, but I anticipate I'm going to need to do a thin layer underneath this.
A2.28 kg according to my ganachulator app.