is there a reliable way to convert sheet gelatin to powdered gelatin for a recipe?

Brandon, I asked the same question a few months back. My first foray failed for whatever reason. I was successful when I used 1.5 packets for 3 sheets of gelatin, I can't recall if it was 2 or 3 sheets but I was making Christina Tosi's cereal milk pannacotta, I can check the recipe when I get home. I also heated the liquid I used for blooming the gelatin ever so slightly in the microwave and that helped too. I know it is supposed to be a no-no but it worked for me. Best of luck.

The brilliant and always entertaining David Lebovitz has an intelligent post here:

http://www.davidlebovitz.com/2009/04/how-to-use-gelatin/

This past pickle question may help you:

http://www.food52.com/foodpickle/7063-gelatin-sheet-vs-gelatin-granules