I know what you mean about the borderline readings at bedtime - hardly conducive to a good night's sleep! If I'm borderline, I don't have carbs with the Baby Bel - for me, the fat and protein in the cheese acts like a half-dose of carbs, which puts my sugar up just enough, without spiking, which it would if I had carbs then. The fat content flattens out the effect.
If I'm definitely too low before bed, then I'll have a slice of toast with some cheese on, but as I'm particularly sensitive to carbs I then have to either inject a couple of units, or end up risking a double-digit reading in the morning, which I don't like, as it throws me for the whole of the next day. Sometimes I have to admit that I wing it a bit and go with just the Baby Bel and cross my fingers, trusting that it'll work out ok.