Hi Charlie,
for Andrew going to bed with bs of 14 after snack and before injection works for him and as his bs levels in the mornings are around 5 then the combination works for him. I know what a struggle it is to balance everything and us poor mums have growth spurts and puberty to deal with as well. When Andrew isn't hungry before bed (which is rarely @10yrs of age!) i reduce the Levemir by 1unit, this works for his morning bs reading, but i find his bs creeps up before lunch.
As for Chloe during the night i would imagine if her levels are highish when tested during the night her bs levels are probably making her toss and turn and sweat, making for an uncomfortable nights sleep. High bs' can cause restless legs during the night, well this it what i find with Andrew, though you would assume bs of 14 high, he does gradually drop during the night.
Not sure if i'm making much sense, it really is trial and error, unfortunately. There will be a time when you manage a full nights sleep, remembering Chloe was only diagnosed in October, and you've both coped remarkably well.
Take care,
Suzi x