In late 1953 or early 1954 I was around the age of 7 living in Artesia, NM, which is around 36 miles East of Roswell.
The neighborhood kids were gathered for a game of kick the can, when a burnt orange sphere around 3' in diameter appeared silently gliding about 4' or 5' above the power lines.
It was moving so slowly that we were able to walk and follow it down the street.
It paused above an intersection that had a large vacant lot on one corner and a small number of houses on the other corners.
I observed within the sphere what at the time I thought was burnt orange smoke swirling within the globe emitting a light that did not illuminate any of the surrounding area.
I also noticed in the center of the sphere was what appeared to be a turning disk that reminded exactly of the disk on the old electric meters of the time.
We followed this sphere giddily as children do, but after it paused it seemed we just as suddenly began to fear it for some reason, and we all ran to our own homes.
I told my folks, of course, they didn't believe me.
After that experience I began seeing UFOs for the rest of my life, particularly through the rest of my childhood.
I had my last encounter in the area when I was 19 years and was preparing to Nam.
I've also seen formations of them, which was witnessed by many high school friends.
When I was 15 years old I was helping a friend as he was flagging for a crop duster in the early predawn hours.
We were West of town and noticed the same type and color of sphere again, but this time it was at a distance of ¼ mile or so and appeared larger that the one that was hovering over the power lines.
It astonished me because it appeared to be at least 6' in diameter from that distance.
It appeared to setting down in a gulley, but we could not investigate because we were needed to assist the crop duster.
I don't know if this relates to the fireballs you've described, but it's closest to any comparison I've ever heard.
I hope this has some relevance for you, so I wanted to share it.
I am now 65 years old, and of all my experiences this is the one that has dogged me every day for all these years.