I will disclose the method to Pedro after filtering out the high level math, but there is nothing in the spreadsheet that is not in Nash's paper.
Nash's paper deals with things far more complex than the pond game. It deals with a wide range of applicability such as Nuclear Arms Race negotiations, trying to get a better raise from your boss, deciding which girl to ask to dance in a crowded room, and plea bargaining a federal conviction.
It works for Pond games too, unless, as previously stated:
1. Some other person also derives the strategy.
2. A "kamikaze" id enters the pond with the sole objective to disrupt your strategy, even though they will lose sooner in doing so.
3. Everyone else messages what they will play, so it is you vs. the pond-dwellers rather than everyone for themself.
Maybe even a group can pool together and cooperate and thereby influence their own self preservation longer than they could if operating alone.
The point is:
This is a mathematics game, which means it can be modeled. It is "small enough" so that every permutation can be plotted.
I don't understand why there is denial over this simple fact.