This is an alternative to the Bee Brain V2 mount and a rubber band as a battery holder. Both work well. Up to you which you like better.
These are printed from TPU and weigh 2g together. That's about a gram less than the Bee Brain V2 mount and a typical rubber band. The models have been designed to be very easy and quick to print and the models are available on Thingiverse as well.
Camera pod - ~1.2g
Battery holder - ~0.8g