I have to admit I'm not entirely sure how the snuza monitor works, is it similar enough to a breathing sensor monitor that you'd feel comfortable switching to that instead?
i had one from Milo for birth (it's the angelcare baby sound and sensor monitor) and I was really happy with it, even when he started rolling around the range it picked up on seemed wide enough that we only had a couple of false alarms.
If it helps about the "paranoia", i used Milo's until he was 1 and a bit
![Embarassed](https://2img.net/i/fa/i/smiles/icon_redface.gif)
so i'm tempted to say do whatever helps you sleep well at night!