rhm

I'd vote for the 165's.

If you want more, here's my thinking on this:

Crank arm length does not seem to matter much. I have come to that conclusion after a lot of experimentation. I found it was easy to get used to cranks as short as 140 mm, and hard to get used to long ones once you get used to short ones. In the course of that experimentation I learned that longer cranks offer no advantage at normal pedaling speeds. If you let your cadence get uncomfortably low (like, when it gets hard to turn the pedals over at all) the leverage of longer cranks will help you get another couple yards up the hill before you start to walk, but that's realistic only in rough off-road situations, not what we encounter randonneuring.

Shorter cranks also have their advantages. The main advantage, I think, is that shorter cranks tend to promote a higher pedaling cadence. So I prefer them for that reason.

I use 165's on just about all my bikes, but 160's on my fixie.

Again, I must emphasize that crank arm length does not seem to matter much. Just as people of all different sizes are able to walk up and down the same stairs, just about anyone can ride 170 mm cranks. It stands to reason that there is an ideal size for each person, and that a smaller person will want shorter cranks, and I'm sure that's true; but there has been very little research into what is actually the ideal size. I have no data to support this claim, but I am convinced shorter is better.