Lakebilly, authentic Neapolitan pizza requires an overwhelming amount of heat- on all sides. An inferno above, as well as an inferno below. Choosing a thicker, more conductive stone increases the transfer to the bottom of the pizza- so much so, that you could very well achieve Neapolitan undercrust leoparding at 700 with this stone. Unfortunately, though, speeding up the bake on the undercrust will only magnify the shortcomings of the top heat, and, in a single stone grill setting, unless you have a rotisserie burner, the top heat is almost nothing. Even with a two stone scenario, with one stone for the hearth an a second for the ceiling, you'll never get Neapolitan leoparding on the top of the pizza. The best top browning you'll ever see in a 75K btu grill is the kind you see on NY style pizza.
Between a 'Neapolitan' pizza with a leoparded undercrust/white, possibly raw top vs. a perfectly baked NY style pie (with a NY style malted flour dough), the NY style wins every time.