One potential problem with having the crossfeed valve open with both sets of wing tank pumps on is that if there is any difference in output pressure from one set of pumps then the fuel will feed from the tank with the higher pressure and cause you an imbalance anyhow and possibly run that tank dry while you are confidently motoring around believing that the fuel is feeding evenly from both tanks.
This imbalance will not occur in the sim as the fuel pumps are computer modelled to be identical. Real life isn’t like that.
Better to stick with the standard procedure.
Regards,
BH.