Since everyone else is reporting, I might as well too with my two flights today. Beautiful clear day!
(Yesterday's three flights were more interesting with gusting crosswinds, clouds and only 1 gallon fuel remaining after one flight.)
Got and installed the 1/4" brass SS ball teflon seal (I think) valve from Home Depot.
Everything sloping down from tank to filter. Flow sensor now vertical.
One flight with fuel cap vent. Some bubbles, not too bad.
One flight without fuel cap vent. More bubbles, pressure below 2 psi at times.
The inlet hole to the flow sensor turbine is only 1/8" !
As this point I'm convinced that I'll never be able to get it 100% bubblefree with the sensor in the line to the pump.

I know I should stop fiddling with this carb setup and change to fuel injection, but...

To get the current setup working right I should:
Tie the pump outlets together, followed by a fuel filter (to dampen the pulses), followed by the flow sensor and then split to carbs, with a shutoff valve in the line to the center carb (for leaning at altitude).

Finn