Tell us about yourself!
I built mine using a clear acrylic sheet and to make it diffuse the light, I sanded it with 220 sand paper on a random orbit sander. I choose to leave the "up" side smooth but you can get more diffusion if you sand both sides.
I chose to put my LED strips on the bottom and I just painted the inside white. It does have a striping pattern to the light, but once you put your tracing source material on top, it's very noticeable. I do think the "wrap-around" method here would be easier to wire as I had to cut mine into strips and join them with clips that were supposed to be no soldering required but I ended up having to solder every one.