It is not possible to determine from your recipe whether the dough is too wet without knowing how much water and how much flour are in your starter. You also indicated two cups of starter, unless that was an error. Either way, we would need to know the composition of your starter. Even then, it will be difficult to come up with a good answer because you are using volume measurements, which can throw off the calculations because of the wide variability in the way that different people measure out ingredients by volume.
As far as the amount of dough to use, if you are after a Neapolitan style, at least from the standpoint of crust thickness, I suggest that you use around ten ounces of dough for a 13" pizza.
It is also possible that your salt level is too high. One tablespoon of salt seems a lot for the amount of flour you are using, even including the contribution of the flour in your one or two cups of starter. Too much salt can excessively toughen the gluten matrix in the dough.