I suspect that the stone is a little large and not allowing enough flow from bottom to top. Did you have the vent open to create heat convection from bottom to top? I also think either heat mass or reflective material (foil) would help redirect heat to help with the pizza toppings.
One of the key things in a wood oven seems to be getting the heat to swirl through the oven and create a hot air cushion over the pizza. This really means getting the exhaust balanced with the heat source.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"I'm Armenian...perhaps...but then again...maybe not..."