I take most of the original poster's suggested supplements, and someone recommended Swedish Flower Pollen (not readily available in health food stores but some online sources) to increase the thickness and whiteness of semen. I drink lots of water here in New Mexico for obvious rehydration reasons. I exercise and work out several times a week (gym and cycling/hiking). Well, I'm also an older guy than most all of you (!) and have no problem cumming, just I don't like the watery consistency of my latter days cum.

It does make a glorious mess, though.....
Despite the heavy supplementation, I can't say I have improved in the "huge loads/copious amounts/hard shooting/creamy consistency" departments -- although I have high libido, great sex, and shoot well, even splatter! -- I'm not sure what the solution might be. I guess I'll just chalk it up to "maturing"....heheh -- but it all still works to the delight of me and my partners. Believe it!
I probably have the most expensive urine in Santa Fe, though -- all those supplements probably just course right on through and out the bladder!
I hope you guys get some positive benefits -- maybe I will too one day.