Gas and Oil Home Heating Furnaces - venturi tee usage question

refinishing first floor. plumber is installing panel radiators. want to be able to use TRV(?) valve on panels to control temp in each room. plumber wants to run a single continuous line with panels in line. TRV would then restrict flow to subsequent radiators and could not then be used. he advised me against having radiators branch off main run of pipe and using venturi tees. claims restiction of water water flow and increasing velocity out of the venturi is not good.
any comments/criticisms will be greatly appreciated.
thanks in advance.

Your plumber seems to only know one type of piping system. DO NOT allow him to loop all the panels in a continuous loop. That isn't a good plan at all. If you run a 1" main and use venturi tees, you will have the system you want. You could also use a 2 pipe reverse return system but is the pump is running and the valves are all closed, you will overheat the circulator. You could install the thermostat in a room that does not have a TRV on that radiator. That way there will be guaranteed flow if there is a call for heat. I would suggest a way to throttle that radiator but not automatically.