I MUCH prefer to use multicavity molds. Frankly, a five or six cavity aluminum mould, using my little manicurists fan enables me to run twenty pounds of bullets in an hour to an hour and a half (using my RCBS bottom pour pot. It literally takes only two seconds for the sprue to harden, then, wearing welders gloves, I open the sprue with my thumb. One positive thing that happens, that I really did not anticipate, is that those two seconds under the fan controls the temp of the mold and it never overheats. Frankly, it is just pure pleasure to cast.
Now, when I use a multicavity iron or brass mold, I limit myself to a four cavity mould. Iron or brass gets too heavy with more cavities. When I was much younger I could handle 8 cavity iron molds without issue, but at 85, a five pound (or greater) mould is not much fun for me. But, I rejoice in the fact that that at 85 I can still get enjoyment out of casting, reloading, and shooting! THAT is something to celebrate, my friends!
Dale53