Speaking for myself, I produce huge loads and have been doing so for years, as a guy with a huge cock and egg-sized balls.
The thing I've noticed over the years is that I don't cum as copiously as I used to (I used to be able to shoot around 15 ropes at a time when I was younger. Now its around 9-10), but its still enough to consistently be considered the heaviest cummer my play partners have ever had.
I've also come to realize that I cum heavier and considerably more when I prolong my PONR (Point Of No Return). Not sure if it was by fluke or by design, but I always enjoyed preventing myself from cumming quickly when I was younger, especially during sex, since I wanted to be physically exhausted when I was done having sex, so I would prevent myself from cumming sometimes for more than an hour. Now that I have more responsibilities and less free time, I tend to keep my sessions to within an hour, which maybe is why I don't cum as much (relative to my personal best, but still exceptional on an absolute level)
I've also been doing kegels on instinct for as long as I can remember, (but I had no idea that it was a thing until a few years ago), which probably is one of the reasons as to why I have strong PC muscles, thus allowing me to prolong my ejaculations.