What the drill size to be use in BB vias?

Hi..
I am trying to work on the six layer PCB board. In that i had configured BB via for the layers what ever to be used in the board. But my doubt is for through hole via i had specified the drill and pad. For the BB via configuration whether we can use the same through hole via size or to provide the new drill and new pad size for the BB via configuration.

BB via definition is pad size should be smaller or larger than through via size. Any idea about the configuration???

Thanks
Regards
Dhamodharan