Looks good and I like the DIY part of this... especially this easy.
I like the second shot (lid on) tone, but shadow is better on last one as you mentioned.
What if you warp while the way with white paper or no tin foil inside? I'm not sure and no way near the experienced, but is it makes light source larger/softer?
Maybe the distance to the subject is also the factor...
I see the potential. Thanks for sharing.