What is the "nipple head height" of a DT Swiss Squorx nipple?

What is the nipple head height of a DT Swiss Squorx Nipple?

I am building a wheel and to calculate the ERD, I must first figure out what the "nipple head height" is.

The rim of choice is a Spank Spike 33 Race 26". The hub of choice is a Profile Elite MTB Elite Single Speed. The nipple of choice is the DT Swiss Squorx Nipple.

Hub Measurements:

Drive Flange Diameter:  60mm
Center to Drive Flange: 31mm
NDS Flange Diameter:    58mm
Center to NDS Flange:   32mm

Nipple Measurements:

Height: 15mm
Nipple Head Height: ????

Spank Measurements:

ERD++: 529

Now according to Spank, they specify their ERD as "ERD++". Below is their FAQ about this – this is why I have to figure out the "nipple head height". For reference they say that the average is 2mm and DSN type is 4mm. So I’m guessing the 15mm is way too much and wrong.