Don't ever even think about trying to use RGB colorspace when you should be using CMYK. I'm very pleased with how the highlights turned out on the mason jar. I ended up using a bounce flash with the wide angle diffuser in addition to ambient light.
On another note, I'm very impresses with Canon's build quality, after slipping, and nearly falling on my camera. The heavy 100mm lens decided to take a nosedive and got mulch all over the lens, but once I cleaned it off every think was fine. Not even a scratch.