The outlet pipes would not tee back together under the floor. Otherwise none of the fixtures would stop running if you turned off just one heater (either heater).
States can help recovery from hurricanes and tornadoes by not requiring due digence or prompt and timely correction of substandard conditions, and by providing continued liability insurance where companies drop homeowners.
having 2 w/h's in series i believe is the most energy efficient.very easy to tell how. c/w in h/w out to c/w in on 2nd w/h then h/w out.The #1 w/h is the work horse it's the one doing the most heating the 2nd w/h is basically a storage tank but will heat if needed.just having a bigger on will help but 2 in series is the way to go.