Good overview of Cannae, but, I see that you are using the present site of the river aufidis (as we see it today). This means you have to place the battle southwest of Cannae where the Romans would had not fought as the land was flat and conducive to cavalry action, in which Hannibal had the superior forces.

Reading Polybius, who was wrong about very little, we find the battle taking place on the eastern side of the river, with the Roman troops between the river and the hills leading up towards the abandoned town of Cannae. Unfortunately, the river as it is now does not provide enough room for a battle.There is simply not enough space between the river and the hills leading to Cannae.

The river as it ran thousands of years ago has likely to have changed course. If it ran westward of where it is now, there would be more room to fight, in the correct locations, at least according to our rather sparse remaining ancient works that chronicle the war.