Personally I would forget about India. The reason being that if the UK falls and the US is putting everything in the pacific then they arent going to be liberated any time soon. If I understand the rules right UK can still build in India but forces in India are severly out of position to be of any help to the Europe UK. If you take the DEI like you propose then you should be in a good cash position to at least occupy the US/UK on the pacific side of the board while Italy/Germany take on Russia. Once Russia and the UK fall the game should be about as good as won.
Again very tough to say for sure without seeing the exact set up of the board but that is the way I think I would go given the information you gave.