I have hunted woodcock & grouse cover with with a 26" 28ga SxS, a 28" 20ga O/U, a 25" (over a Cutts) 20ga M12, a 27 3/4" 12ga SxS, a 29" 16ga SxS & others that I can't remember & I've sometimes had the bbls hit saplings while mounting the gun & or swinging on a target with all of them. That's just part of hunting heavy cover.
The length of the bbls makes no difference at all & to think that 3" or 4" of bbl is going to matter is ridiculous marketing hype.
What does make a difference, is having a gun that is balanced so you can comfortably carry it muzzle up in your trigger hand while you push through the brush with the off hand. Having something between 6 & 6 1/4 lbs works well for me. Any thing heavier requires the gun to be balanced too far to the rear for a smooth swing.
