I suspect that even a token British and Commonwealth troop commitment would have been sufficient. Sometimes it is less important how many troops as much as there are other countries. Britain would need to the cost covered and generous debt relief.
What is important for the Americans to understand that this was not like WW1 or WW2 with large battles. Instead it is more like the Philippines insurrection, the Central American and Caribbean interventions. Another examples was the Indian campaigns in the Southwest which if my memory was right had weeks of patrols with suddenly ambushes followed by weeks of patrols. There will not necessary be one battle that you could point to to say this when we won.
The long term key is recruiting the local people to fight on your side.
What is important for the Americans to understand that this was not like WW1 or WW2 with large battles. Instead it is more like the Philippines insurrection, the Central American and Caribbean interventions. Another examples was the Indian campaigns in the Southwest which if my memory was right had weeks of patrols with suddenly ambushes followed by weeks of patrols. There will not necessary be one battle that you could point to to say this when we won.
The long term key is recruiting the local people to fight on your side.