Sometimes, time permitting, allow for a couple of minutes talking to technicians
A good hint to prefer FWD Left main pump is that between the 2 left pumps, that one is the easiest to be accessed by the maintanance staff in case of replacement.
To get to the other one, they say, is far more complicated
However, you have no restrictions to use whichever pump you prefer, such as one on the right side (crossfeed open) to balance the fuel.