I know this wont be of much help & please First wait for this "to be confirmed" by those that know for sure
Edit
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(I cant confirm this, after some searching trying to)
I am guessing you asking specifically to the VSX160 type
which I suspect is a later Eco version (seems to be from below)
so not sure on this at all
seems there may be differences from this post here
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=32977#Post32977maybe a search of the members area if you made a donation might well help
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If you suspect its been tinkered with before you then there is chance its set wrong or not optimal
I cant help with orientation but seems you know where you at on that score
From what little I know
for the white one's as far as I am aware pretty much all
are set to " C "....
(no idea on the black poppet's)
from a quick search except the "Vortex" (A) according to Gregory's manual 54 84...(got to find mine)
so a little dated for the VSX
Here's a post on these forums that offers a bit more that "might" answer partly your query
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=11656Wait for one of the old hands to answer thought.
they'll know for sure... I am a noob
