Since there's multiple different variants of battle towers, it might be good to have a different texture and or model for each, we'd make them ourselves if need be.
Eg, a sandy one for the desert tower, an icy one for the ice tower, a mushroom one for the fungal tower, if a nether tower gets added one for there as well. Potentially have different effects they can give?

Additionally had an, optional for backwards compatibility defaults to stone model and textures, line for custom tower definitions to assign which model, if additional models are used otherwise only texture selecting, it's boss uses and of course allow assigning new textures the same way.