The best way to work with a dream feed is to get them at the right place in their sleep cycle. You don't want them to wake up, or they will sleep worse, waking more frequently. But you don't want them to be so asleep that they won't eat.
Try him at different intervals according to when you put him to sleep. Usually between 2-3 hrs after bedtime.
And with any changes, try to only make one at a time, like Tracy says. Give him time to adjust to a new schedule, it sounds like he is already making great progress.