I'd be a bit concerned about using too longer breaker bar as it could allow excessive torque. Although I use an MG style pressed steel tool of similar length my 600mm breaker bar would work fine allowing a couple of good nudges to ensure adequate spinner tightness.
It's the releasing not the tightening that the bar is needed for and to which John's comments applied I think..
I tighten my centrelocks with a 2' bar and release with an 8' bar attached.
