Here is some outdoor tests. I placed the chips on a piece of coro so I could move it around easily.
The photos don't show as much as I can see with my eyes. Not surprising.
First Test: Full Sun (afternoon low in sky)

Under full sun, the dyes are virtually invisible except for the stained color they impregnated into the plastic. The UV glow aspect is totally lost due to the brightness of the white light. Looking closely I can see the Electric Blue glowing slightly. Very slightly. But if I am that close, duh, I am going to pick up the drone because it ain't lost anymore!. It will not assist in finding it on a sunny day. None of them will. So that portion is completely shot as far as a possible aid.
Next Test: Shade on a Full Sun day
Next, under shady conditions, I can see that the Electric Blue, of all of them, is the only one that shows clearly where it had been dyed and where it hadn't. Even from a few feet away I could see the slight blue tint. So perhaps when mixed with a white light visible color, it could help. Almost. The Atomic Purple was visible close but from afar, almost not so its a wash as are the rest of the colors including, surprisingly, the Blizzard blue which I couldn't distinguish unless I looked really really hard.
Here is a crop of one image showing the chip:

Even in this photo you can see the slight purplish blue on the lower 3/4 of the chip. Its quite a bit more obvious to the human eye.
Last Test: Window light mixed with Interior Incandescent
Indoors with window light its very similar to being outside in the shade. Electric Blue is the obvious winner.
I still need to photo them on a cloudy day as a final test.
I suppose next clear moonlit night, I can drag the chips out and see how they would play in that scenario. Many of us do fly at night.
Would the visibility be worth buying a jar at $2.25? Iffy at best. Worth $9.95 for a 4oz jar? No. Absolutely not. Unless you had another use for it after you dyed your props. Say Halloween decorations, rave parties or just screwing around (invisible ink for example). But I think you can get virtually the same color and intensity of glow under UV using Tonic water (which contains quinine). So, maybe not worth it there either. And if you have washed the fabric and its white, the electric blue can't be seen on the cloth as the whitener that ALL fabric soaps contain now already makes white glow as much as this dye does. If you are staining plastics or some other material like paper or burlap, ok, might be useful.
About the only way these would actually aid in locating your Phantom is if you were searching at night with a UV flashlight. Then, I guarantee they would pop! All of them. But if that is your scenario you want to go for then I would rank them in this order:
1. Electric Blue
2. Blizzard Blue
3. Atomic Purple
4. Nuclear Green
The rest are rather muddy in dim UV. The first three will produce a purplish blue, the fourth will yield either a neon green or a muddy yellow-green depending on the UV strength.
As of now, the only promising one is Electric Blue. What color to mix it with for RIT is another thing. Since its bluish I would lean toward any of the colors with a blue component such as the ProLine Neon Green (blue+yellow) or one of the lime green consumer ones (also blue+yellow). Possible candidates:
1 Neon Green
2 Lemon Yellow
3 Teal
4 Aquamarine
I may pull the trigger on the 1# bag of the Neon Green. Of those colors, its the one likely not to exist in nature. And also likely the most useful for other projects around Halloween. I can't imagine anything else around here I might like to have any of the three remaining colors.
So I guess until I get a cloudy day, moonlit night or decide which RIT I want to go with, thats kinda the end of the experiment.