I just finished these cakes. They are an order with style selected from my Flickr album.
In general, I spend around 2 weeks on making cake from air dry polymer clay for overall process and to let the clay dry completely.
These cakes are in 1:12th scale. The wedding cake has 1" (~25 mm) diameter at the widest point while the 1-tier cakes have ~3/4" (20 mm) diameter.
I found out that some collectors have slightly bigger diameter cake collection (1" - 1 3/16" or ~25-30 mm diameter) while the other would like to have their cake diameter at ~3/4" (18-22 mm)...