How much simulated oil(water I guess) are you putting in the oil pan when you do your slosh test? Not all 5 quarts will be in the deep part of the sump with the engine running.
I agree that oil moves around in the pan under hard acceleration and turns.
Racers and performance engine designers have been putting fences, one way doors and swinging oil pump pickups to keep the pickup submerged probably as long as racing has been around.
This is one of those deals where about anything done will help. Just keep good clearance for the crankshaft and rods.
