Just tried the one where you don't get the openning cut scene ,and the Romans start on the other side of the river.
Really recomenned all it ,if you think the battle starts to soon.
The battle I just played took a good 20 minutes or so.
Should give a better feel for how the battles in the final game will feel.
Also ,there's a mod where you lose the green arrows ,which I know a few don't care much for.