Another lefty here. You'll never notice the spent shells flying.
Personally I think port-loading a right handed gun is easier when shooting left handed too. I wear my shell pouch on my right side, so I simply drop my right hand off the fore end, grab a shell, drop it in the chamber, and my right thumb hits the bolt-release on its way back to the fore end. It's pretty intuitive, and after watching right handed shooters load their semi's, they just look awkward.
For a righty, they have to roll the gun almost 90* so they can see in the ejection port, drop a shell in, then roll the gun back around, reach under the receiver with their left hand to hit the bolt release, then re mount the gun. I imagine that's why Browning developed the speed-load feature...
For us lefties, we simply roll the gun maybe 20*, drop the shell in, hit the button and remount. It's a much quicker and smoother set of motions...
If after some freak accident, I woke up tomorrow and were right-handed, I'd probably throw my gun away and go buy a left-handed semi-auto shotgun, for the reason state above.