Sounds like it should work fine. A lot easier than the way I did mine.....dropped about 20+ feet of underbelly, starting in the “utility area” of the basement, then snaked”, “fished”, “cussed” the gas line thru the frame crossmembers and 6 to 8 inches of “dirty” fiberglass insulation, came up thru the floor at the island , and mounted the heater on the island end. Then, had the “opportunity” to put the underbelly back together!
We already had one CO detector, but added another as a “ffailsafe” system! Unlikely that both would fail at the same time!