The official pinstripe layout by BMW is as follows:
Wide line: 5mm
Narrow line: 1,5mm
Distance between the two lines: 4mm
Since pin striping was done by hand, it’s normal that these values were not consistent. We have an original BMW new old stock fender and we have taken multiple measurements, just to see how much variation there is. This is just 1 fender: obviously there will also be a variation between fenders.
Wide line: consistently 5 mm
Narrow line: consistently 1.5 mm
Distance between the 2 lines: varies from ~4 mm to ~5.5 mm
Distance between fender edge and wide line: varies from ~7 mm to ~14 mm (near the fender outer ends)

The width of the narrow line is pretty consistent at 1.5 mm

So is the width of the 5 mm wide line

The distance between the 2 lines varies from +- 4 mm to +- 5.5 mm in the curves

LH side

RH side

RH front side

RH back side

LH back side

LH front side

Nice detail: on the inside, the initials of the person who did the pin striping