Drilled that hole and fit that leg. Haven't made photo, maybe tomorrow.
Actually I'm par lying, partially had to chisel it out. Some lessons are getting digested right now.

No photo but here's a drawing. The leg fits bit more loose then was intended because as I cranked the drill, it moved left and right widening cavity. The end of the leg also isn't perfect round shaped so by default it had a direction where it was thinner. Above all this I had to debark it further slimming it. But its unevenness has its advantages because it also makes it stuck at places.
It does not fall off, despite it went in kinda easily. Beside those unevenness I suspect forces in the play too. It isn't shoved in vertically but the whole thing is in an angle, which means as the gravity pulls it straight down at the edge of the hole and at the top of the leg it gets pressed to the wall of the hole, keeping it secure in place.