If you go with 2 or 4 you'll need to either run the power cord up behind the motherboard tray to the top or mount your PSU forward of the motherboard on the floor of the case. In order to use the original l G5 PSU case you'll need to shift the back panel upwards and either use a Micro ATX board or cut the top shelf to clearance a full ATX board.
Edit: from your post in someone else's topic I see you're using a E-ATX board which means that mounting a PSU on the floor forward of the board may not work.