Shotguns
John Bidwell
As someone who prefers to shoot Sporting and Skeet I would choose the slimmer Schnabel because it puts my forward hand closer to the barrels and therefore the axis of the gun.

This help direct the muzzles to a target when the moving gun is brought to the shoulder.

Fore-ends with a wider beavertail shape come into their own for the trap disciplines where the gun is pre-mounted before a bird is called, but for all other shooting where instinctive reactions are needed to align the barrels to a fast-moving target, then a slimmer Schnabel is best.

This happy state of affairs is more easily attained when both hands (not just the one controlling the fore-end wood) are as near to the centre of the gun as possible.