That is excellent work, Wade! Thanks for sharing them, and particular the details about their creation. It is really helpful for others (like me) interested in meteor photography. A few questions/comments:
1) From your number of 5000 images x 25s / 4 cameras / 2 nights I assume you let the cameras stay exposing for about 9-10h per night. Since you did not use tracking mounts on the last 3, how did you avoid motion blur on the stars due to Earth's rotation? Also, it looks like the meteor streaks converge from a single point, despite the meteors being distributed over the night. Did you "move" the meteors to the appropriate positions in post? Did you have to take into account the variable distortion over the field of view? No matter how you did it, it looks good anyway.
2) I see no non-gemenid meteors, did you exclude them? You also removed satellites, airplanes, I assume?
3) Why did you stop down the TS-E 17/4Ls? Interesting that you have TWO of them! Or perhaps you actually used the Zeiss 15/2.8 on the second 5D3 (why else would you rent the Zeiss)?
4) Have you captured the same meteor in different cameras? I'm sure you have, I just couldn't see it easily by looking quickly.
5) It is interesting to me that the Gemenids show so much less colour than do the Perseids. Perhaps it has to do with the composition of the grains, or it is related to the relative velocity between Earth and the meteoroid orbits. I have not researched, just speculation...
6) I think your captures of the meteors are already perfected, so a next step for you would probably be to find some interesting foreground object to improve the composition and impact of the images, as in this example
by extremeinstability on this forum. Another challenge would be to attempt capturing meteors at longer focal lengths.