Ok I get your frustrations, and by the way I might reduce my carbs when I'm high BSL but no way do low carb in the same way as others on here preach. For example my breakfast can be anything from 90 to 110 grams of carbs plus which gives you some idea what an old fart can do.
So your Nova sounds like it is working as it should, eat stuff and yep carbs get absorbed and then get dealt with by Nova over a period of about 3 to 5 hours.
So let's try this another way. None of us know what our ratio is, we all start at 1:10 it's just a starting point and then people adjust
So you know about carb counting? Have a look at "Bertie online" it's a good starting point.
Your on a fixed dose of 8 units so let's say that's 80 grams of carbs, that could be easily 2 weetabix, think there 32 each. That should cover you, but weetabix, like all cereals, are slow to absorb so you will spike and then come down. Hopefully not as high as 21 but I don't know.
I don't want to say anything else because your seeing you DSN, but certainly ask about it, you could even try saying you don't think the Nova is working and see if anything else is suggested.
Saying all that your long acting Lantus may also play a part in this. It is meant to be a 24 hour back ground insulin but many find it does not last that long. Again something to talk about with your DSN.
As for "low carb" yes it works for some but not others, certainly both me and
@porl69 don't not sure about
@therower.
@Mel dCP does but only because she has other food allergies but I still greatly admire what she does.
And as for frustrations, yes T1 can frustrate the living daylights out of me and others too.