JimDandy,
I cannot imagine a worse thing to do than to shoot a shotgun off of a bench. It tells me that you are aiming rather than pointing. I am am an advocate/shooter/practitioner/student of the "instinctive" or Churchill method. Basically this means that your gun is an extension of your anatomy that is pointed (like your index finger would be) in a dynamic manner to precisely where you want the shot to go to hit a moving target. This means that your gun mount must be utterly consistent and correct with your target focus and that your gun must match your anatomy so that your visual focus matches where the shot will go. You don't aim at all. You concentrate on the leading edge of the target and make sure that your physical alignment and gun extension are consistent with hitting it. If needed, your gun needs to be adjusted to agree with your anatomy and POI. Thats why shotgun dimensions - length of pull, drop at comb, cast off, etc., etc., are all very, very important and proper gun mounting and "staying with the shot" are critical. I can't do the subject justice on a post here, but the Orvis Wingshooting guide by Bruce Bowlin is as good as any on the subject.
As far as patterning goes - you shouldn't mix that (patterning) specific evaluation with your shooting technique or "hunting" analysis. It is a totally separate issue, and a less subjective one. You need an even, and dense enough pattern (with enough velocity and shot mass) at a given range to "get the job done". It is well worth the time and effort to see what your pattern looks like at different ranges on a patterning board. In this (wonderful) era of changeable choke tubes, etc. you would be doing yourself a disservice by testing your shotgun's and shell's effectiveness only by hunting results.
Believe me, there are quantifiable ways to understand and exploit the art and science of good wingshooting which can improve your success and reduce your wasted money and your disappointment. Learn the basics of wingshooting, gun fit, and technique. Pattern your gun with the load your are using at various ranges. Make sure that the combination of your gun and your visual point of concentration (sight) are where your pattern is centered upon. Make sure you are using the best load for your requirements.
Nothing beats "real world" hunting experience, but to suggest that experiential hunting results without the knowledge of how all of the pieces fit together is a superior strategy just doesn't square with my experience or strategy for success.