I have always ran my propane tanks one at a time. My thoughts were if there were a serious leak developed it would only drain the tank that was open. I monitor my volume with the Mopeka system and when the volume in the open tank becomes low enough to be of concern I switch it off, turn on the other and plan to refill the empty at first convenience.
John & Linda
2015 Timber Ridge 260RLS
2019 Ram 3500 Bighorn 6.7L Cummins