Some of My Results (Groups)
Before summarizing the group characteristics that generate the best Total Ethics, it is instructive to examine some results that are unique to the least and most cohesive groups.
Many Strategies/Many Tax Rates is the least cohesive.  Members use different ethical strategies, and contribute unequally to group welfare.  The Unequal Tax Rates actually create a sub-group of Free Riders, making this group function less ethically than a simple no-group population.  It would be better to have no formal group at all, than to have a Many Strategies/Many Tax Rates group.
The Same Strategy/Same Tax Rate is the most cohesive.  All Agents practice the same ethical strategy, and all contribute equally toward the group.  In theory, there are no defectors or Free Riders, though the temptation toward both is strong.  This was the one group structure where the Group Treasury came near (but not quite) to compensating members for their contributions to the Group Treasury.  Only a Same Tax Rate group could have a Group Treasury greater than zero.  And only if all members practiced the same ethical strategy could they all make truly equal contributions to that Group Treasury.  So group members received nearly as much as they contributed.  The only decrement in group gain was the presence of non-zero Tax Rates, which reduced the incentive toward Self-Gain.
The Same Strategy/Same Tax Rate group was also the only scenario where the presence of Good Will does not decrease Equality.  In all other scenarios, any increase in Other-Gain was accompanied by a decrease in Self-Gain, which decreases Equality.  If all Agents practice Good Will, and all have Equal Tax Rates, then the inverse relationship between Self-Gain and Other-Gain disappears.  Where both Self-Gain and Other-Gain increase simultaneously, Equality increases.
The Same Strategy/Same Tax Rate group benefits from the amplification of Self-Gain when Good Will accompanies effective Self-Gain Basic Strategies.  The Same Strategy/Many Tax Rates groups also benefit from this amplification, but this benefit rises even more where no Tax Rate differential distorts the relationship between Self-Gain and Other-Gain.  The most optimistic Basic Strategies (Best Cell & Best Row) enjoy the greatest benefit, as compared to equally effective, but defensive (Minimize Loss) Basic Strategies.
It is worth studying the many layers of group structure described in the preceding paragraph.  It illustrates how different factors amplify their effects so that the final result far exceeds the sum of the individual factors:
Same Strategy – Self-Gain and Other-Gain are now positively correlated.  An increase in one causes an increase in the other.
Practice an efficacious Self-Gain Basic Strategy – Self-Gain surges, and Other-Gain increases with it.
Practice Good Will – Other Gain surges, and Self-Gain rises with it.
Same Tax Rate – Eliminate the distortion that causes Self-Gain to decrease as Other-Gain is artificially increased.
The optimistic Basic Strategies fare best, because the stark competitive trade-off between Self-Gain and Other-Gain has been reversed.
So just what are the best group characteristics to foster Total Ethics?  The first requirement is an Equal Tax Rate.  The Group Treasury will be greater than zero.  There will be no artificial enhancement of Other-Gain at the greater expense of Self-Loss or group loss.  Equality of outcome increases.  Total Adjusted Self-Gain will be greater (compared to Unequal Tax Rates).  Good Will generates less Inequality.
The second requirement is a Low Tax Rate.  A 0% Tax Rate is actually the best, because it creates no disincentive from Self-Gain.  But if a non-zero Tax Rate is necessary, then lower is better than higher.  The Total Adjusted Self-Gain will be greater.  The Basic Strategies will retain their effectiveness in acquiring Self-Gain.  Other-Gain can be attained without artificially decreasing Self-Gain.
The third requirement is that group members practice the same overall ethical strategy.  Even if that strategy is relatively ineffective, there will still be a positive relationship between Self-Gain and Other-Gain, rather than a negative relationship.  There will also be a greater Equality of outcome.
Assuming the group practices the same overall ethical strategy, the Basic Strategy underlying it should be effective in Self-Gain (Best Row, Minimize Loss, or Best Cell).  Even in highly competitive situations, effectively pursuing Self-Gain still increases Total Adjusted Self-Gain.  In extremely competitive encounters, Minimize Loss is probably better.  In less competitive encounters, Best Cell or Best Row are probably better.
These four characteristics are merely the prerequisites.  Once they are in place, Good Will is able to generate a great increase in Ethical Outcome.  With the final addition of Good Will, nearly all ethical indices surge.  As group members practice Good Will toward each other, its beneficial effects amplify gain for all.  It is here that we see the accelerated incentive toward Good Will within a group.