I've run a lot of hard tanks with fixed pickups in .049 powered RC planes and unless you maintain perfectly flat inverted flight for at least 10 seconds.... your engine will continue to run until it warns you that you either need to roll over or else watch the engine quit. Random splash into the fuel pickup is enough to keep the engine running and the fuel droplets will reassemble themselves into a solid stream by the time it gets to the spray bar.
Working with .020 or .010 I figure these engines will be that much more forgiving about using a fixed pick up in the tank.
For this reason a fixed fuel pickup is a good choice unless you are planning on flying inverted for big blocks of time once the tank is empty enough to prevent any fuel splash into the hungry feed line. .