Let's put this in perspective. Your poles are highlighted in yellow on this relative stiffness chart (courtesy of skyjumpers.com).
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- kalnmitc's poles.JPG (10.93 KiB) Viewed 2976 times
You 160 and 170 are almost identical in flex, your 13-6 165 is 5 pounds lighter, and your 14-0 165 is 5 pounds heavier.
So it will depend on your grip whether you should use the 160 or 170.
As RG said, start with the 13-6 165 with your standards ALL the way back ... to 80 cm (31.5") ... and see if you're blowing thru that too. You probably are.
Then move up to the 160 or 170 ... with the SAME grip ... and again with standards at 80 ... and see if you're blowing thru. If you're not blowing thru, then you can start inching up your grip. If not, try the 14-0 165.
You don't mention your grip from the butt ... only from the top. This can be confusing, since 2 of your poles are 13-6 and 2 are 14-0. Always refer to the grip distance from the butt. What are they? Your grip should be on the tip of your tongue.
And always keep the SAME grip when moving up a pole ... no matter what the pole length. Once you're landing well into the pit ... then you can inch up your grip ... but not before.
You have the luxury of having 3 poles bigger than the one you're blowing thru. So I'd ALWAYS keep the standards at 80, and not even adjust them. It's one less thing to worry about ... it's the fastest way to improve your technique QUICKLY ... and it's safer. Instead, adjust your grip slightly one way or the other ... on one of your 3 heavier poles.
Kirk