I guess I'm overly cautious on this subject, but there's no way I go to bed with the on-board generator running....even with a Genturi attached. I've been in Emergency Services for the past 30 years and I've seen CO poisoning in houses first hand. One came from just idling a car to warm it up in an attached garage at a house.
I brought the CO meter from my office to the house to check the CO level inside the motorhome with the generator running. Without the generator running the level was zero, as expected.....with the generator running it ranged from 9ppm to 35ppm, depending on where I was testing. With the Genturi installed, it did reduce it to 7ppm throughout but any level of CO while I'm sleeping is too much for me.
If you REALLY want to know, contact someone with your local fire department and ask if they would be willing to do a CO test inside your coach while the generator is running. Then you'll know for sure if there are any exhaust leaks BEFORE you try to get a good night's rest with the generator running. My recommendation is to NOT try it......
Just my $0.02 worth....
