not sure if this is any help - but this is what we do at the moment -
Swaddle - put down awake in cot - when i go to bed and give him a feed around 10:30ish, i swap the swaddle for a sleeping bag - if he is asleep/drowsy at the time he has no problem sleeping till 5/6ish ( he does toss and turn, and lift his feet up and bang on mattress, but all with eyes closed!)
Is there any way that you can swaddle to get to sleep - then say half our later put in a sleeping bag? - I am not sure if what Reuben has is part of the startle reflex, or something different, but the reason we still need to swaddle is cos he 'boxes' with his fists, and it stops him from sleeping. The above might not work if your LO wakes at small noises, but may be worth a try?