How much extra threading is there on a 14mm versus a 12mm nipple?

I have 14mm DT Swiss nipples.

Right now, my spokes don't stick out of the head of the nipples.



If I went and bought 12mm nipples instead of new spokes, this may solve my problem if I get at least 2mm of threading above nipple head.

From what I've been reading, threading is difference is about 1 or 2mm. So which is it for DT Swiss spokes and nipples?