It is difficult to estimate thickness factor from just a photo, and especially one where the cross section of the pizza is not visible. To cite an example, Mellow Mushroom pizzas typically have oversized rims yet are reasonably thin in the middle. Typical photos of MM pizzas can be seen at http://www.google.com/search?q=mellow+mushroom+pizza&client=safari&hl=en&source=lnms&tbm=isch&sa=X&ei=oP7rU5qVJ5GqyAS2pYLwDg&ved=0CAgQ_AUoAQ
. MM makes three sizes of pizzas, 10", 14", and 16". The corresponding thickness factors are around 0.15, 0.12 and 0.12, respectively. Looking at just the rim alone might be deceiving in estimating the thickness factor.
Some pizzas are also made with skins that are left to proof (rise) in a pan or disk before dressing and baking. Seeing the risen skin might lead one to miscalculate the thickness factor.
The dilemma is that a dough ball with a given weight can be used to make a skin with a large or oversized rim, a skin that has a medium sized rim, a skin that has no rim (e.g., a cracker style dough), or a skin that is allowed to rise before using.
It might help in this case to see a cross sectional view of the rim and center crust and try to relate it to a crust where we know the thickness factor. Even better yet would be to ask the pizza maker what weight of dough is used to make a given size pizza. This is how we came up with the thickness factors of the MM skins.