Hoyt,
Regarding your question:
According to Robin Baker (see "Sperm Wars: The Science of Sex," 1996, 319 pp), the volume of a man's ejaculate is proportional to the size of his testicles (i.e., larger testicles => larger ejaculate volume).
Baker states that the frequency of a man's orgasms is proportional to the rate at which his testicles generate new sperm. Most men have 3 or 4 orgasms per week. (This seems somewhat low to me, but that's what he says.) A "4 orgasms per week" man with an active sex partner might have all of them by fucking his partner. If his partner is less active, he might have (say) 2 by fucking his partner and 2 by masturbating.... or 1 by fucking his partner, 2 by masturbating, plus 1 nocturnal emission = 4 per week. Or, if he doesn't have a partner, he might masturbate (say) 3 times and have 1 nocturnal emission, again summing to 4 ejaculations per week.
Baker doesn't comment on whether a man with given testicle size can increase the volume of his ejaculate on (for instance) the weekend by voluntarily refraining from masturbating during the week and "edging." I suspect he might argue that such a man would have more nocturnal emissions, such that the total volume of his ejaculate at the end of the week would be about the same.... but he doesn't say that.
Baker's book (if he's right) would seem to call into question the idea that a woman can increase the volume of her man's ejaculate by requiring him to wear a chastity device for which she is sole key holder, and allowing him release only at more-or-less widely-spaced intervals. Although Baker doesn't address this situation either, his comments would seem to imply such a man would slough off excess sperm and semen via nocturnal and daytime leakage, such that the weekly volume of his ejaculate would remain about the same. But, I don't actually know that.
The above doesn't answer your question, unfortunately, but I thought you might find it of interest.
Thanks for the photos of your hot and sexy 42 year-old wife. She's gorgeous, and could easily pass for much younger. What a babe....
—Custer