J-44466-12 Fuel jumper

We have a couple of 2001 4.3 vortec's in our family, and Astro and a Blazer. I just got the OTC 7448A fuel injector cleaner as a gift. In the OTC manual it says simply pull the fuel pump relay and run the cleaner at around 55psi, but I've seen GM bulletins that talk about using the J-44466-12 & 11 jumper blocks on the plenum and fuel lines and running a cleaner at 75 psi. Can anybody shed some light on this? I actually ordered a Kent Moore kit with all the jumper blocks, so I can go either way. Are the blocks simply used so you can run a higher pressure thru the injectors? If you use the block to jump the lines together, I'm assuming you just leave the relay in and let the pump cycle then?

Thanks in advance!