Achieving 'glossy', ultra smooth pudding texture
Without the actual recipe to work with it's hard to suggest precise modifications (I don't have the cookbook you mention), but it's quite possible that store-bought puddings have more gelatin and/or gum-like ingredients. Gelatin can be added to a ganache (normally some combination of chocolate and cream, with a low-gloss finish) to achieve a "mirror glaze", which has a very smooth, consistent, high-gloss surface. Perhaps adding a bit more gelatin (and liquid?) to your recipe will get you there.