Hi Tomtom congratulation on your bikes. The drilling was being performed where the previous outside cable guids have been riveted so there have been holes already, the internal cabling was being performed through holes that have been done where the cable guids were, by a carbon specialist. The hole in the down tube is necessary to fit the internal Di2 harness. The battery is in the seat post.

are you running 8 speed?

No, running 10 speed why?