header length to equalizer pipe

is there a maximum length you can run from the T on the main to the equalizer pipe? tough to explain but the single riser comes up from the boiler to a 90 into a 12" horizontal nipple into the T which feeds the supply, on the other side of the T will be close to a 24" horizontal run to get to the equalizer pipe going into the hartford loop. Also can there be a 45 on that same 24" run or does it have to be a strait shot? forgive the tough explination, i am replacing my boiler and trying to pipe into the existing hartford loop/equalizer setup and into the supply, but my new Burnham's feeds exit differently than my old boiler as does the vent. any help will be appreciated. thanks, Gary from Boston