I think you are right not to want to bet our life on something. There are a lot of things to consider, and I agree that carbon monoxide is a pretty important factor. What type of filtering does it offer.
Anytime, I am building something that requires this much attention to detail, I always like to consult the pros. You might be able to find someone via angieslist.com
that has the ability to show you exactly what you need. That will include what the unit you are considering has and doesn't have. It's always better safe than sorry!