[Al Skierkiewicz]

Part one of your answer lies here...
<R77> The relief valve must be attached directly to the compressor. Teams are not allowed to adjust the 125-psi relief valve.

If you are asking as to which port the relief valve is located, the answer is either side that is convenient they are both output ports.
If you are asking, can you have two of your storage tanks be on the low pressure side, then the answer lies here in <R76>...
B. Only the compressor, relief valve, pressure switch, pressure vent plug valve, pressure gauge, storage tanks, tubing, and connecting fittings may be in the high-pressure pneumatic circuit upstream from the regulator.

This gives you max storage anyway. You may have an additional regulator(s) on the low pressure side following the main 60 psi regulator.