Matt, I don' t know where I got the 13 I was just typing that up fast didn' t realize everything had to be exact.

I have a 28 inch draw
I have 28 inch arrows at 9.5grain per inch w/100grain tips.
I was chronoed at 225 and then I cranked my bow up 10 more pounds and added 1 inch in to my draw length so I assumed it was around 240.

How much KE is requiered for these heads? What is the formula for KE? thanks -Sam