Played around with making a "more proper" light box with a cardboard box and gluing printer paper in in. Still not sure I like the results. I may need to rub wax or oil on the paper to let more diffuse light in.
have you tried using a white screen from your phone/tablet/laptop? by holding a phone or tablet above, you could add the little bit of extra lighting that you want.
I haven't since it would screw with my white balance and I can more closely calibrate it with the bulbs since I know their Kelvin color temp. I think I need brighter bulbs in the 1500+ lumen range instead of nearly 1000 lumens.
With the screen or the tablet you can open a webpage or image editor and change the background / lightning to get the light you want - it can be then 'hardcore' white or warm or red or blue or whatever. With the brightness settings it can also be adjusted. When you use the light box or a white paper as background they are always a great source for white balance though, so it is then easy to change what you need or want.
I tried to white balance your shots and it works not bad at all, but I don't know what your goal is there - to have a white, absolute white background with totally correct colors of the caps? Maybe a flash would be easier, like using bulbs. Mine is in the middle range and it can be so strong that I have to weaken it!
