Hello Delta
My son is 13 and has been diagnosed since mid-Nov -- so we are all pretty new here, I guess. Anyway, my understanding is like bev's: levermir for background only, and the addition of novorapid injections with a reasonable amount of food, eg more than 14 g carbs (tho, as mentioned before on this forum, even this raises him. It's just that the levermir manages to bring him down again. Usually!)
My only rather strong thought is along with Northerner's -- I would be very wary of giving novorapid last thing at night. You cannot really yet predict your son's reaction to novorapid, and anyway nighttime reaction seems different.... so I'd give only a small snack at night if he's hungry or low. We've stopped having an automatic snack at night -- but my son's older and may therefore take this in his stride more easily?
My son is on 17 levermir per day, split 8 in morning, 9 at night. His current ratios are 1:8 in the morning, 1:10 at lunch, and 1:12 with evening meal. He eats a huge breakfast, so will normally have 35g cereal, and two pieces of toast or egg, tomatoes, bacon, one piece of toast etc. Sometimes he has porridge instead of cereal. Unless he wakes high, we stick with a cap of 8 units on breakfast (at 9units, his tendency is to hypo, whatever he's had for breakfast). If high, we will go to 9units if he doesn't do PE or Games first thing. Etc!
The rest of his meals vary a lot. Most packed lunches are 50-60g carb, eg 5-6 units. Dinners can be anything from 8 units down to 3 units, depending on carb content.
I've lost my train of thought...does this reply help at all?!