Well done on getting this done!
One question, what happens to non-US customers of the SE store, do they bother to order?
I personally don't order stuff* online if it has to come from the U.S. - not even from amazon. I don't think I am alone in this, although lots of people do buy from over the pond.
The UK punches above its weight in the online world, I believe a lot of readership comes from good ole Blighty.
You might want to approach Chain Reaction Cycles or Wiggle to carry these bottles. They will need copy + picture for the product page. You know the trade price for bottles - they pay less than you do, so I doubt that SE will be making their first million from CRC/Wiggle selling these bottles. You'll be doing well if they pay carriage - expect that to be 'volumetric' rather than 'by gross weight'.