K-Jet fuel return line.

Been going through the process of measuring fuel pressure because car has low power and I suspect fuel starvation.
System pressure is only 1.5 to 2 bar. Trying to verify if it is a blockage or fuel pump problem and have a couple of questions.
1. Can a fuel pump still work but have weak flow?
2 On the FD which is the return line. Is it the one coming off at an angle tqwards the bottom of the picture or is it the one on the right side of the pic?
Want to do a volume test and from what i have read you measure the flow from the return line.

Control pressure went up to 48 PSI after about 10 minutes.(measured with electric plug on WUR disconnected)

Thanks