Andy,
Are you able to assess whether the Super Sniper on a dual plane is susceptible to more distribution issues than carb? There have been comments that TBI and DP are not a good match, I suspect based on at least that Engine Masters episode.
Not sure about the intake part, but I have noticed on the FiTech form where some people have had injectors that were not flowing the same. A few of the problems were related to debris plugging the injectors, and leaking injector "O"-rings.
After I plumb the fuel system, I connect the fuel supply line to the return line where they would normally connect to the fuel rail, and then run the EFI pump for a minute to make sure any debris in the lines is flushed back to the fuel tank. Last time I did this, I used one of the cheap Summit filters with the -6 AN connectors on each end and the small disc screen filter in it. This way i was able to inspect the screen filter to see if any junk was in the supply line (which there was a small piece of rubber hose.)
This is the filter I used to "loop" the supply and return lines.
I had the filter from my old carbed truck.
https://www.summitracing.com/parts/sum-230101/overview/I would not use the filter above in EFI application, and there is not much filter area in the screen. This is a link to the replacement screen filter if you want to see what it looks like.
https://www.summitracing.com/parts/sum-230110
