I have a wood and steel they are both 14 inches wide. Lenght is about 27 for the steel, 24 for wood.
That said, you must modify the wood, sand it before use with 150 grit then at least 220 grit with a palm sander.
Once you have baby's butt smooth, treat it with cutting board oil let dry a few hours, then oil it again try to buff it in.
Let it stand overnight before use.
The steel if for removing and adjustments.
The wood if for launch.
About launching, I DO NOT use cornmeal I use semolina flour on the peel only. I find that it much more ball bearing like than corn meal. After I launch the pizza I notice that most is still on the peel threfore not that much under the pizza.
It can be bought in small packeges, I have it in one of those sprinkle shaker along with another for AP flour to be used for the stretch.