I much dislike attacking stone walls of any sort with any sort of good/bad infantry, but this is because I never played any good-assault-infantry faction to the stage where they actually could train good assault infantry. I prefer to attack wooden walls because they give my slingers and archers a clear field of fire over them, and because the defenders all start out just behind the walls, it means my slingers get a wonderful chance to decimate them as they scatter like quails to run out of range. Then as they get out of range, i advance my rams, prompting them to move forwards again to defend the breaches, allowing my slingers to kill more of them! And get this: while archers have only 12 or 15 arrows, slingers have 40 bullets, and their lethality IIRC is higher.

If I HAVE to attack stone walls, though, I prefer to advance at most two towers. Location is not a priority as long as I advance them at blind spots. I sometimes like to put two towers at two corners of the city, then advance towards the gatehouse. THat way I capture an entire front of the walls while I'm at it. Defending units don't really suffer from my captured towers nowadays, because they know to keep themselves in the town square, and anyhow, the cities I capture don't seem to have very effective machineguns when turned inwards to face the city interior. And has anyone noted Eastern stone walls don't fire inwards, fullstop? THat happened to me when I captured Carthage.