Glass on single fin for a 5'10" grom board

Hi everyone,

I am planning on shaping my kid a short board, 5’10". I am wanting to glass on a single fin because that is what I like to do, and am wondering what you guys think as far as fin size and placement? I was thinking about a 7" fairly raked fin, but wasn’t sure how far to set the leading edge in from the tail? Thanks for your input!

 

For an ever changing grom I would go with a long box. 

They gain and loose weight and grow real quick. 1/2 inch of movement makes a difference on a single.