So far as "hex-headed version" goes, the Uncle Mike's that were made for the ROA 12-28tpi application were made to mimic the original Ruger nipple wrench profile. From what I've been able to see from the product photos, the metric sized (6x.75mm) version have the standard two flat nipple profile like the original Pietta nipples.
Pale grey unpolished stainless is fine by me,I don't need bright shiny to convince me of anything.
How do the nipples compare to the original equipment Pietta nipples?
Is the flash hole or flame channel or striking surface of any remarkable difference from the original Pietta nipples?