Better to put pump in tank, but if pumps you got have the pressure you need you can really put them anywhere.
Better in tank because ALL pumps like pushing better than pulling and the pump behind the pressure head stops all vapor lock. Easy to fuel-cool the pump in tank too. Easier to get going too if you run out of gas. Many modern electric fuel pumps will burn up if they are not primed instantly, or why all car owners manuals now say to never run out of gas. As little as 60 seconds running dry can tear them up.