If you really want to know, then you are looking at statistical analysis of each pattern and you will need five to ten patterns per load. We aren't talking about just counting the holes, either. You have to know where the holes are. The only tool I know of that does this is the patterning analysis program based on digital photos of patterns that Dr. Andrew Jones has out. It is still a lot of work, but the results are real.
Any shooting activity is fun, IMO. You will learn from patterning. Unfortunately, you will also be tempted to "learn" too much from the data you collect. There is a lot of variation among patterns shot with the same gun and identical loads. The only way to account for said variation is to include a lot (5 to 10) of patterns in your analysis.
Post back if you care to discuss further.
