Many years ago I got into sewing items made from vinyl (looks like leather) and found that top stitching was almost
impossible. I don't know where I got the idea, but I got a jar of petroleum jelly and spread a light coating on the area where I would be stitching. Worked like magic. I made tote bags and diaper bags...and all the straps needed
to be top stitched since they had the edges folded in, not made into tube and turned. Perhaps this idea will work on the leather as well. I once did a remake of a pair of leather slacks into a mini skirt. No problem, but it was lighter weight than upholstery leather. This was an easy solution.
June in Cincinnati