Here's what I know.
1) I bet cash that the Holley techies think you have a drag style fuel cell with bottom fed pick-ups. That's why they're telling you to mount it low, so gravity can assist. Holley pumps designs do not pull nearly as well as they push. (however they self-prime better than other designs) With your cell, moving the pump down will not fix anything.
2) If you call dedicated fuel system manufacturers, like Aeromotive, QuikFuel, etc, they will tell you that you'd be best off with a return style fuel system. Why a return system? because the pump will pull north of 75gph just sitting there at idle, thereby pulling mass amounts of fuel through the pump and cooling it off. A general rule is you want to keep the pump close to the tank, and the regulator close to the carb. Its really easy to plumb. The return can go in the port on top of your fuel cell that (according to your picture) is currently not used.
Return styles are all I use now for the last 15+ years. Before that I had all kinds of problems with idle and "pressure creep" I always carried a spare pump because I was planning on it's failure. Now I can get several season out of a pump.
AND- The filter is a canister. The ends are sealed with o-rings and unscrew and expose the micron filter. I just took this pic of my spare.
Trying to help, hope this didn't sound argumentative.