If it’s a similar design on the 169, without boost pumps there should be no significant pressure disparity, so just make sure that crossfeed is open (as you said Outwest).
That's the problem, it has been mentioned in this thread that the 169 does not have a crossfeed valve. So, if that is the case then the only other option would be an interconnect valve ( like a 212) to allow fuel to flow between the 2 sides.