Would you not be tempted to run them in series? That way if one pump failed/went open circuit both would stop working, rather than one failing which could mean running lean?

http://www.bosch.com.au/car_parts/en.../fuelpumps.pdf

The 044 has a max continuous current rating of 15.5A so imagine a max continuous rating of 31A. 4mm2 tri rated cable would be fine for this with a resistance of circa 10m Ohms would mean a voltage drop of 0.31V. I suspect the pumps would on average draw less than 12A each.

The other option would be to use a circuit which monitored pump current and disabled both pumps together if one failed..?