in lockout mode, once it sags (to the 30-35%), does it still move/bob after that? if it doesn't move, that sagged position would probably be beneficial. i.e. i am assuming you'd mainly be locking it out when climbing, so tilting the bike forward would get you in a better pedaling position, especially when it gets steeper.
i am not familiar with the lockout characteristics of modern sids. my last sid was a 26er (maybe 2011 model).