Did you give any thought to using mirror images to give a ramp down and then up for the progression? Perhaps going down from top left to bottom left at full, then heading from full to a sliver at bottom right, then progressing up to top right at full and heading left back to nothing on the left.
Sorry if that sounds confusing. It would create a square crop image with full moons at the bottom left and top right corners, and near black in the bottom right and top left corners. If it wasn't two hours past me 'bedtime', I'd probably have a stab at it.
Looks fantastic btw! |