I was asked about this recently so here's my two cents on baking with flower nails. I stumbled upon this use of a flower nail a few years ago. It is now standard practice in my kitchen. When I bake a cake I place a flower nail upside down in the cake pan. The purpose is to promote even baking of the cake. Ever have a cake that gets done on the outside but takes forever to bake on the inside? This is especially a problem with large cakes. Yes, there are heating cores that you can use. I have one. You'll see why I like the nails better in a minute. Here's how I do it.
On larger cakes I sometimes use more than one nail. On my 11 x 15 pan, for example, I use two nails, equally distributed in the pan.
Give it a try, I think you'll like it.