A lot of EFI cars these days run pumps with the regulator in the tank, fixed fuel pressure, dead headed.
As far as yours is concerned, I would do this:
Main line fit a tee of your line size say 8AN, the straight run is the main flow to the engine. The tee goes to the regulator, the regulator sets the fuel pressure and dumps the excess to the return line.
Aeroflow Male Flare TEE 8AN Black ALL Sides Male AN AF824 08BLK | eBay
After the tee on the straight run to the engine split the line with a y block:
8 AN Flare TO 6 AN Flare Union Billet Y Block Compatible Speedflow Proflow | eBay
Up to the rails -6 line. Cap the front ends of the rails semi-permanently.
AEM 2 604 High Volume Fuel Rail Port Plug 6 9 16" 18 | eBay
1 2" NPT Aluminium Port Plug Block OFF Blanking Allen HEX Socket Fitting Black | eBay
All examples of course.
Gary