The gauge matters very little. An appropriate shot charge through an appropriate choke is what matters. After that, the question is: does a smaller than normal/average/recommended shot charge through a tighter than normal/average/recommended choke(tight enough to produce a lethal number of hits on the target with the reduced number of pellets) make a pattern of a size with which you can be reasonably assured of hitting the target. I assure you that Mike Yardley and Dig Hadoke can be successful with smaller patterns than can most shooters.
Shot charge weight, shot size, choke, and target area are bound at the hip. Ask yourself if you have the skill to ethically shoot at a living target with X/8 oz shot which will allow y% of the aiming error of the normally recommended charge.
