I hold my gun fairly tight, I use my weak hand to do about 80% of my gripping and my strong hand only lightly holds the stock ( I shoot right handed by the way). That way i have no tension in my hand slowing down my trigger finger and as I load weak hand load 2 and quads I am able to just drop the gun down under my arm and let the stock just roll in my strong hand until the loading port faces up. I tend to hold the gun fairly snug to my shoulder but not so tight that the gun is shaking when I hold it. I took a class with Igor Jankovic who is the IPSC World Shotgun Champion in Modified division and that was the way he suggested to hold the gun. He also suggested putting grip tape on the fore end and the recoil pad to make sure you had as much grip on the gun as possible and to stop the gun from accidentally sliping out of your shoulder.
I find it works you may not, play around with it and see what feels comfortable