Stinson Voyager 108-1 - 1946

Hello:
I am working on a 46 stinson tail drager as a project and have a
question as I am wiring it from scratch,
I accessed the battery box which is in the aft section of the airplane
and found the master relay mounted on the side of the battery box , as
stated in AC43 the relay should be within 2 feet from the battery,
this seems to be right, The question is since I am installing a Radio
Master switch , should the relay be intalled in the same place with
the master relay and run another battery cable forward or could it go
on the firewall and have the master relay supply power to the radio
master relay.
Thank you for any help.