The stitching looks better on the wrist than off. I would have gone for grey rather than white.
I usually deeply press in a furrow for stitching to lay into, that straightens it up nicely.
I used various home made tools for the purpose, made from old scrappers or sheet metal curved to match any curvature on the work piece.
The leather is soaked then allowed to dry slowly so its a bit expanded then pressed and punched while very slightly moist.
Dye and finishing is done before stitching.