Hi Tim, I would suggest to chose the type of Long SUP around 11' with the same feeling you would chose your favorite proned longboard. I mean just chose same kind of outline, rocker, fin position up to your style and local wave .Long SUP is the same with just a bit pull out dimensions to fit around 140liters of buoyancy to allow you to stand up paddling your new longboard.
I wish to you that holding a paddle walking on to the nose will become natural and fun soon