Since my post in the main Stranger Things thread, I've received many PMs and inquiries. Seemed easiest to keep one response in a separate thread.
The video clips below give some idea of what this material looks like. While the installed video came out darker than reality for much of it (phone would auto-adjust and I was using one hand to flip), it still gives a good idea of the huge difference it makes.
I purchased the screen material here, and would recommend having 5 sample sheets (it's possible this will prove to be difficult): https://shop.elitescreens.com/store/p127/Sample_Screen_Material.html
This is the adhesive sheeting I used (I also ordered the more expensive 3M sheets, but found this cheaper option to be the easiest to work with): amazon.com link »
To achieve the results seen in the installed video, I also have 1-3 layers of cardstock in all of the large arrow inserts and some of the smaller inserts closer to the screen. Also, the back half of my right flasher is blocked with a piece of black vinyl, the lighting is dimmed in the game through settings, and I made partial cones to go over the sling LEDs (still some room to better darken this area from the screen, which perhaps I'll do later). I also pulled the LED near the shooter lane exit and it was one of the worst offenders.
Can download the parts and see instructions for the billboard and bulb cones here: https://www.thingiverse.com/thing:4825295
You'll have to figure out which direction is appropriate (they're not guaranteed to be one way or the other on the sheet as I received them both ways).
When turned the proper way, the image will be perfectly viewable at all 180 degrees from the bottom to the top, but standing further than at the corner of the game left to right will start to show the ambient light rejecting feature this material has. So no matter how tall or short you are, the game will look stellar from player perspective.
When the material is received with the proper direction being the slimmest, you'll likely need to carefully remove the adhesive to get enough height for the main screen panel (the front can be rolled off, but the back may need some help with contact cleaner--alcohol will ruin the material, and goo gone was messy).
Before cuts are made to the screen material, cut enough double sided tape sheet to cover an entire sample. After pulling the one side, with it on a flat surface, line up the screen materials and carefully apply it flat (I held the other end taught and something like a credit card to slowly push the material down into place to avoid air bubbles).
For the main panel: I placed the material over the factory white panels. It was best to cut the bottom, left, and right sides to proper size beforehand. All sides could be done that way, but I chose to use an exacto knife at the top. I used a sliding cutter for most straight cuts..similar to this: amazon.com link »
For the drops: I removed the drop asssembly from underneath and removed the old decals (cleaned any remaining adhesive with 91% alcohol). With one flat side at the lower end, and the rest cut oversized, apply the material one target at a time, cutting around the edge with an exacto knife to be a perfect fit--this is larger and better looking than the smaller factory size. I found the most accurate cut to be achieved when holding the blade angled in a bit toward the material side, and holding some pressure against the target.
Ramps: These may be tricky for some. I used card stock and progressively made many cuts until I got a nearly perfect shape of the ramp decals. It's best to remove the factory pieces, but I left them in. I cut the created template in half and placed them on top of the screen material, taping them all to a large piece of glass (any hard surface will do). IMPORTANT--the screen material MUST be cut in the proper direction--templates should be laid straight up and down, not at an angle--otherwise the result will be darker and likely different between both halves).
With that arrangement for the ramp pieces, I cut around the template with an exacto knife. Test the cut before pulling the backing for installation.
Spinner: I did the same as above, but used the decal replacement that came with the game as a template (I only applied to the side facing the player when it's at rest).
Stand up targets: Apply directly over the factory piece (this keeps the rivet from interfering). Can cut to the size of the supplied replacements.
Billboard: If using my 3D file, cut to fit (I used cardstock here as well after painting and clearing).
Perhaps this will help some. Please feel free to let me know what I'm forgetting or what I could make clearer.
Sorry for the blurry billboard photos (didn't pull the glass, and would lose my ball before I could get a good shot )