This is an outstanding thread! thanks to all...

So, if the problem seems to be cavitation of the fuel flowing through the porous bag due to too much flow impedance making the fuel "boil" from the low pressure on the suction side, perhaps what's worth a try is two UAT's in parallel each with half the flow. So long as both stay full, the only thing that's really being given up is twice as much fuel "tied up" in the UATs. At least worth a try on the test stand, I'd say...

Dave McQueeney