Maybe it's a bit early to say since I haven't cut this branch and potted it yet but it appears that in about five weeks one could have a fair sized branch rooted and in the ground. Why isn't air layering done instead of trying to root cuttings?

I think that usually people try to root cuttings of varieties that they don't already have.

Here is the branch as of today. Some roots are showing through the plastic wrap now, about five weeks after preparing it.

Will that root ball be big enough to support that tree?

Yeehova, it didn't look so bad when I prepared it but now that it's leafed out, I think you are right. I may need to prune off some leaves several days before I cut the branch off.

Here is an update on the air layered fig experiment. I clipped off all but a few leaves and let the tree heal for a couple of days before cutting off the branch. For the size of the branch, there really weren't very many roots. I potted it and left it in the shade.

Here is the potted branch.

After four weeks, it has recently been pushing out lots of new leaves so yesterday I re-potted it to a corner in an outdoor shower. It had roots winding around inside the pot walls already. Maybe this technique was overkill for a fig but I was happy it worked. I did a lemon branch at the same time and had to leave it on the tree four weeks longer than the fig.