It's tough to match colors on subjects shot under high color temperature lights without setting the color temperature in software.
A substantial part of the art of digital photography is deciding on the right combinations of settings (ISO, fstop, shutterspeed, focus) to produce the image you're after. And those settings are interrelated, where changing one affects the others.
Keep playing with manual focus, ISO settings and shooting in Av mode. Experiment with settings. Crank the ISO up as high as it will go and notice how your shutterspeed is faster, but the picture gets noisier. Set the ISO down low and notice how your shutterspeed is slower but the noise / "grain" goes away.
Try picking a "medium" ISO and playing with fstops. Use the biggest f stop number and notice how more is in focus around the focal plane but a longer shutterspeed was necessary. Try the smallest fstop number and notice how your shutterspeed can be much faster but the distance from the focal plane in which items are in focus has decreased.
From the angle I'm seeing on the frag plugs it looks like you're not shooting straight through the glass. It is an annoying limitation, but it is really important. I remember looking at my not sharp, not clear pics going "Huh???" . Then a lightbulb went off over my head as I noticed my shot was at an angle, trying to get a better view of the top of the piece. I went back and shot the subject again, this time straight through the glass and the subject was sharp and clear. Try it yourself.