Best bet is to:
1) Mark the old ones before removing them. Such as white out on the exposed threads.
2) Pop them out without touching the adjuster sleeve.
3) Double check your marks to make sure they haven't adjusted in or out during removal.
4) Assemble the new ones next to the old ones to ensure the exact same length with equal threading on both ends.
5) Mark them like you did the old ones.
7) Check your markings to ensure that they haven't adjusted during install.
That method is as close to original specs as you are going to get without talking to someone much smarter than me