I did try that. I don't think I can get the RRC pump to seal.
The mounting flange is made in such a way it needs a raised ring on the tank, and that means I've to weld a ring on to the tank. Didn't work.
My plan of fitting the RRC pump to the series sender avoids that problem. As does the external pump.
Or pumps: twin tanks.
Or is the HP RRC pump a different mount? Would it mount flush to sheet metal?
Plus it needs extending, too.
External is making a lot of sense, acestetic considerations aside.