Originally Posted by Quel

I don't see why you think your back is less flat. Looks noticeably more flat to me. That position looks 10 times better to me than what you started with. I'd start hitting the road and making whatever necessary power/comfort adjustments from there.

Originally Posted by Racer Ex

The new position looks much more sustainable. When you ride make note of any rocking of the torso and/or hips, if you're moving fore/aft on the saddle, and where you might be experiencing soreness.