ABaking my 1st 14"x22" sheet cake in a new "Fat Daddio's" pan . Should I use one heating core or two? Or just flower nails and how many? Thanks!

I personally don't like heater cores. I would use 3-4 flower nails in that size a pan.

AThank you! I have never liked them either, but had never gone this big a sheet cake yet!

I use Ateco heating cores---flat, stainless steel, blunt things similar to flower nails, but better. 

In a 14x22, I'd put 4 of them across the long axis of the pan.  I put 3 across my 12x18 and it works extremely well.