Hi - I'm a new guy - so YMMV with this idea that I use.
At your local fabric store I buy this dual sided interfacing with some loft (some of it gets pretty cushiony) that I like - its sticky when heated with an iron. I cut a shape slightly smaller than the soft lining I use, then iron it on. I peel the other side, fold the edges in place, and then mount it to the leather. Then, I slap it on a machine or use waxed linen (four-thread) to handstitch it on.
the interfacing creates the padding and cushion, and sticks to the leather to finish the work. Even if it comes off the lining and the leather, its stitched into place already so the interfacing in essence becomes a floating pad.
Peace
Duskshade
