Herman--
You may be right. I haven't done much of this yet. Recently, I've only tried it with the three cuttings mentioned above (two GeorgiaFig White Hybrid Unknowns and an LSU Purple) and they may be unusually vigorous and sun-tolerant. Still, I don't see any signs of stress. The leaves are small at first, but they seem very healthy and well balanced with the tiny root system. A few years ago, before joining the forum, I tried sticking a few dormant pieces of my Brown Turkey in pots of potting soil, outside (in full sun) where they would get a little water every day from my vegetable garden's irrigation system. All but one died, but the survivor rooted just fine and didn't seem to have any problems with the sun.
I don't have a Calvert and I'm not sure how to tell whether something is a real cultivar, but I hope to try more experiments when I can get some spare cuttings. I like GeorgiaFig's approach--rooting figs outdoors in a specially-prepared soil bed. I have a small, raised bed, filled (as best I can remember) with about 30% native soil, 50% composted cactus pads, and 20% steer manure. I'm currently using it for green beans but I think it would also work nicely for fig cuttings. The main difference would be that mine is in full sun and I think John's cutting bed gets filtered shade from a larger fig tree. I plan to bury cuttings completely (and vertically), but with the tops a half inch or so below the surface to keep them from drying out.
Last year with my UCD cuttings I had decent success (beginner's luck), despite mold problems and some die-off after potting-up from bags to one-gallon milk jugs. Initially they were kept too wet, and all the transitioning from humid-to-dry and shade-to-sun only compounded the problem. I also think Dan's (SemperFicus) warnings about CO2 being trapped around the roots probably explains most of the die-off. So, it seems as if starting them out in the same environment they'll ultimately be growing in would help avoid these problems.
My guess is that as long as they grow roots before growing leaves, they should do okay, although any cutting that gets leaves before it develops roots would probably die because it wouldn't able to take up enough moisture to replace what is lost through the leaves. At any rate, the best way to find out is to give it a try. When I do, I'll take photos and post the results.