D shaped seat post - bright ideas needed?

[asgard]

Looking for a bit of advice. Currently riding a Giant Defy Advanced 1 and keen to move to a more aero position for triathlon. The challenge is the seat post is d-shaped. I can't find any reversible/forward biased seat posts that are d-shaped!
Current saddle has short rails but I suspect one with long rails will not provide the necessary adjustments. Keen to see if anyone has any bright ideas before I commit to the n+1 rule.

[frisbee]

Can you reassemble the clamp to gain a couple of cm or is it symmetrical?

[asgard]

Good point, and something I have not checked to be honest (or know how to). Will ask google and take a look tomorrow. Thanks!

[esuuv]

You said it yourself - n+1 clearly applies here...........

[asgard]

Well, nearly my birthday after all.....