I'm afraid there is no way to save a default bullet scheme
that can be applied with the standard Bullet button of the
Formatting toolbar. Instead, what you need to do is to
modify your template to include a paragraph style
formatted with bullets, and then apply the proper style
each time you need that specific bullet formatting.

Note that once you've got a bullet style properly setup
you can replace the standard Bullet toolbar button with a
customized one that applies the desired style (and thus
also the proper bullet formatting).

Stefan