I'm trying to edit someone's sci-fi novel, and I'm running into a need to refer to levels of gravity in a space station and on other planets in terms of Earth gravity. I cannot find a correct standard for this. Would it be 0.3 g? 0.3 G? 0.3 Gs? 0.3 G's?
And generally it's desirable to spell out units of measure in fiction, I think, but that doesn't really work here, does it? "A third of Earth's gravity" is a fine workaround when it's seldom needed, but when the concept comes up a lot, the correct unit is necessary.
I have had no luck Googling this; believe me, I tried. I'm not even sure if conceptually what I'm dealing with is G (Newton's gravitational constant) or g-force. I have seen both "g" and "G's" used in various places, but what I'm looking for is the accepted standard for use in science fiction novels.
EDIT: For clarity's sake, I should mention that almost all the main characters are humans from Earth or space stations near Earth, so the perspective is based on Earth gravity.