Which regad edge tool?

[Husky3]

I am looking for a head for a regad creaser I am going to purchase.  I need to use it to create a groove for the stitching.  I want it to be approximately 4mm from the edge.  I am using .6mm tiger thread.  Will one of the FN series work?   Most everything I see only goes up to 3mm from the edge.

[Markjedis]

Forget using a regad for a stitch groove keep it for edging grooves. Many of us use a pair of dividers or a screw adjustable crease to get a stitch line.  I prefer to use a groover such as the one below.  With a bit of practice you can get the stitching to be just below flush which stops any wear or use a smasher (polished hammer head) to set the stitching so it’s flush to start with and settles to about 0.25mm below the surface of the leather.

https://www.tandyleather.eu/en/product/craftool-pro-stitching-groover-set

https://www.tandyleather.eu/en/product/craftool-adjustable-creaser

I am in no way connected to Tandy. Just easy to use for reference.

[zuludog]

I no longer use a stitching groover, I just use a pair of dividers to mark the stitch line, followed by stitching chisels along that line. You can set the dividers to any distance you want