I get numb hands when I put too much weight or pressure on them. Usually, this means the bars are too low or the reach is too great. I agree with others: install a stem with shorter reach and/or flip the bars up. Check the saddle position. If it's too far aft, you might be able to shorten the reach by moving the saddle forward a bit. Also, you might try pointing the nose of the saddle up a little. If the nose points too far down, it can cause one to slide forward, putting additional pressure on the hands to maintain saddle position. Judging from the photo, this could be an issue.
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Steve