There was some debate about weather the leaves has to be up right. I guess you cleared that up. Myself, I have a hard time rooting leaves. No mater what, they just rot. Every once in a while I am successful but can't tell you why.
Stush

this is the cutting that was first upside down, note the point
shape was done to increase surface area for rooting (an experiment) So this little pup took over 2 years! Sans are
the most amazing plants!
Fred

Well done! There are some good pics and info here and here.

I've only done the water thing once (with 2 leaves,) the leaf thing maybe a dozen times over the years and also can't decide if I think the water props were actually faster, or, as you said, being able to notice the slightest developments immediately made it seem so.

My latest experiment was putting 5 leaves in the ground in April. No pups yet... but it's been a very dry summer and these aren't being coddled with supplemental water. The plan was to give them away around this time, but IDK what I'll do with them now, probably wimp out (not being able to watch them freeze to death) and try to cram them into my house. There's already way too much, this is silly to even be doing.

I've sent plants to about a dozen people this fall, including the trimmed leaves that were too tall to fit in a box. Hopefully some of them will pop in here & talk about their exploits... Even if the connection comes from facebook, I always encourage visiting GW Sans forum!

The spot where these were in the ground since April ended up having less light than I thought it would. Dug up yesterday. They were buried about halfway, which in retrospect, was probably much more deep than necessary but I knew nobody would be watering them.

After digging these up after 6 months, it definitely went faster in water than this, and so much more fun to watch than glancing at leaf stumps buried in soil occasionally and observing, "Nope, nothing's changed whatsoever at all in any way..." What's it doing? No idea... Never had either way fail, but still, in soil's a total snooze. I don't propagate plants to do it in the most politically correct way, but to amuse myself. So much time elapsed between burial and excavation. Without x-ray vision, the exciting developments were not visible. End result = same, but level of amusement, vastly different.

For soil *or* water, let callous at least overnight, up to a few days.

In water, not enough experience to say what's ideal, but I chose to keep a steady 1/2-3/4 inch of water. That worked. Since it was a clear container, I could see the tiny pup as soon as it started forming, and it turned green from the start. Definitely amusing ;)

Thanks for the pictures of your outdoor experiment. Years
ago when I lived in Florida, I had Sansevieria Trifaciata in the landscaping. It grew like a weed. One day I went about wacking it back and I left a dozen or so leaves lying
on the lawn in the shade. I forgot about them and when I finally remembered the "debis" I found they had started to root them selves into the lawn! (you can grow anything in Florida, LOL)