ADDENDUM #1
The Neutrals
If, or when to, activate the Neutrals, is a very big part of any OOB Global 1940 game. While it does not happen in every game, it certainly happens enough to prove that it is an important dynamic to the game.
Both sides should be consistently paying careful attention to “Should I go for the Neutrals?” as the game progresses. Looking for the key indicators that show the Player that “Yes, now is the time to attack the Neutrals.”
Typically, there are three reasons to go for the Neutrals:
Axis #1: The Allies have left their SZ91 fleet exposed if the Neutrals are attacked by Italy, specifically Spain, and that allows the Germans to annihilate a large Allied fleet on the cheap.
Allies #1: The game has come to a standstill and neither side may improve their position as the board is deadlocked. By accepting a short-term disadvantage, the Allies will gain a long-term advantage that may swing the game in the Allied favor.
Allies #2: As you mentioned, the Allies are not making sufficient progress in landings on the European coast so they revert to the simpler strategy of landing in Spain.
Normally, it is the Allies who are attacking the Neutrals and typically they will set up such an attack by being prepared to hit Spain (USA), Portugal (USA), Venezuela (USA), Saudi Arabia (UK) and Turkey (UK) all on the same Turn. In later Turns Chile plus Argentina (USA) and Angola plus Mozambique (UK) are taken. Typically, killing these 28 infantries results in about 11-13 Allied losses or about $36 worth of troops on average.
The gain in income for the Allies is $15 a Turn. The Axis will usually gain 8 infantries from Switzerland (2) and Sweden (6), or $24 worth of troops, and $3 a Turn in income from Sweden. That means the total initial loss for the Allies is 60 TUV. ($36 in troops killed plus $24 of infantries gained by the Axis). Compare this to the $12 per Turn increase in income and you can see it takes about 5 Turns for the Allies to recoup their initial losses and start making gains from their strategic decision.
Therefore, as long as the initial loss of 11-13 troops does not prove to be a large detriment to the Allied cause, and the Allies can last at least those 5 Turns, then making the attack on the Neutrals makes sense.
By the way, you will notice I did not include Afghanistan as usually the Axis are not able to gain those 4 troops because either they can never liberate them or the Allies kill them at a loss of usually 1 ground unit.
Finally, I did not include Mongolia as typically by the time one of the Powers attacks the Neutrals Mongolia has already been turned Russian by Japanese activation. If, Mongolia is still a strict neutral at this time they too would slide over to the other side as Pro Allies.
