Shame he's got some nappy rash, otherwise you could just skip some of the nappy changes during the night (if it's not too dirty a nappy), and that'd help keep him calm.

Yep, their routine does change eventually, although without a proper experiment with twins, it's hard to know whether it's correlation or causation in terms of you trying to manipulate things with waking him.

How's the breastfeeding going?