Incredible work. Be careful with the choice of adhesive for things like these graphic overlays though. There are a couple different approaches. The best quality is to take your original artwork to a professional photo lab and have a transparency made on film. You can get a Duratrans, for example, which is professional, commercial quality and can be made archival to resist fading over time. They have some other processes as well and the colors and detail will be brilliant. Not cheap, but then again this is very small artwork so it won't hurt the wallet too bad.
There are two basic types of transparency film, one is clear and the other has a milky white base. If you choose clear you should mount it to milk plexiglass (which is translucent but not bright white, it literally looks like milk). If you choose the other type you can mount it on clear plexiglass.
The other option is to print to acetate using a color laser copier. This will look great but won't be archival quality and so it might fade over time with exposure to UV. In fact, it is very likely to fade.
Special, archival quality spray adhesives should be used for stuff like this. Anything else will yellow over time, some drastically. 3M makes some of the best stuff, ask the photo lab what they use to laminate archival-quality transparencies onto plexiglass. That carpet tape you used is very likely to turn yellow with age -- Ugh.
The key is using ARCHIVAL quality materials. You've put an enormous amount of effort into something like this, so going cheap on materials will only hurt in the long run.
Finally, you need to protect your work from UV rays as much as possible. Most light sources emit UV radiation and that will fade your beautiful work over time. One solution is to use fiber optic illumination. The fiber can filter out the UV. But make sure to use UV-filtering gels or coatings between the light source and the fiber to be sure that none of the UV gets through and ends up radiating onto your work.
Again, GREAT JOB on these, all comments are meant to help only and no criticism intended.