Where/how to locate combo voltage regulator/inverter on '78 cb550?

I Recently bought a 1978 CB550K and the wiring pretty bad.  So, I'm installing a new wiring harness and fuse block.  I also bought the combo voltage regulator/inverter.  Can anyone recommend how/where to mount this unit.  It is larger than the individual parts it is replacing, and has different mounting.  I've removed the left side mounting plate, and removed the old parts, but still not sure what the best way to mount the new is?

Thanks,

Dave