Bolg's warg base

Hello,

First of all I'm sorry for my writing, I'm not used to write in English.

I was discussing with a friend of mine about The Hobbit profiles and he realized that Bolg's warg doesn't have any specific base size (such as Thranduil's elk or Azog's White Warg) so I assume that his warg has to be put in a 40 mm base

Is there anywhere where this is clarified? If so please tell me where it is.

Thank you in advance.