Ok, so quick update. I bought a set of 165 sram rival cranks on ebay for $120. I figured at that price it was worth it to see if it helped and is a step in the right direction. I took off the 172.5s mounted them up and also raised my seat about 8mm. I've ridden 3 days and about 70 - 80 miles like this.
Verdict is: Definitely an improvement. It's subtle, but I feel like I can definitely get lower for longer and with a straighter back. Staying in a full aero in the lowest part of the drops while peddling is still a bit of a tall order, but besides that it does seem to be helping.
Now the question is, if I should go even shorter, and if so how much more. I need to figure out how short I would need for the maximal improvement in terms of my aero positions, but without going so short that it sacrifices performance in other areas.
I plan to ride with the 165s for a while and slowly gather research and probably go to the pro bike fitter in town eventually and see what he thinks.
That's all the news.