Any battle tops?
Of course! 
There will be at least one. It will probably be of the "precision" type, everybody throwing simultaneously into a raised platform, the last one standing getting the points. We will need to secure some kind of platform once there. 
What tops are used for this?
Depends of what people have, but not bigger than a Giulia. If everybody has a fixed tip, that's what we use.
Why a platform? I'd say if you have to, a circle of chalk would be sufficient if it was acceptable. Otherwise, a length of rope or string or even paracord to make a rough circle. But, if one wants to spend a little money(which I don't recomend), I'm sure they have plastic wading pools or hula hoops. I just figure a stick of yard chalk or some cord would be easy to stuff into a pocket or luggage and someone probably already has one or both of these items.
Wasn't the battle top of choice at Nationals a wooden fixed axle that one was supposed to put a bottle cap on the crown? Anyone selling those? While I"ll probably never use it for battling, it would be a good item to have around and be familiar with.
Whatever happens, it definitely sounds like people are going to have a lot of fun at Worlds!
