If you increase the radius you will increase the volume, even if it is secondary. Volume is what this discussion is about. You're splitting hairs, don't you think?
There may be manufacturing considerations, but in general corners are stronger because they have a tight radius. The neck has a tighter radius too. The height doesn't matter, because the linear stress uses this equation:
And once again, you're wrong, but you're right sometimes. http://eagar.mit.edu/EagarPapers/Eagar206.pdf
Please note the following in the results:
"However, for all bottles that did not fail at artificially-
induced discontinuities (including bottles
with no induced discontinuities), fracture initiated
at the base of the bottle. Figure 1 shows one such
bottle, which broke at 2.25 MPa. This is most likely
due to the stress concentration present where the
side of the bottle joins the base."
IE the corners, which are almost always weak points.
As for the green bottles you mentioned, the thicker walls could be for added strength or it could be for asthetics. Keep in mind that manufacturing processes can change the strength of glass.