Joebob. You say that you want to install a recirculating pump, but then you are considering a system that doesn’t have a loop. where are you recirculating to? Joebob the recirculating pump should be placed on the return line & the water recirculated into the colder section of the HWS.
Get a Master Plumber to correctly size the system & install the correct valves. You may need two recirculating pumps to operate alternatly. You may even use heat trace on dead leags & forget the recirculating pumps, but with heat trace you must properly size & lag the system.