Kweber,
I love my set up. Krieghoff built the gun starting with a Big five Classic action 470 NE, then added the 9.3x74R barrels. The 7x65R barrels were added later. I believe the setup is like a skeetgun set, one receiver for 12, 20, 28, and 410 gauge.
The 470 balances well and swings well. The 9.3x74R is a wounderful setup also shouldering and swinging well with a good balance point. The 7x65R much like a 410 setup is a little butt heavy or light in the muzzle. It's also a little heavy to carry around for deer size game but I love it anyway and will carry the extra wieght without complaint. They make a set of 20 gauge barrels. I don't know how they will balance or shoot but the moment I can convince my wife I have to have it for my birthday it's mine.
My double is also stocked left handed.