Technically (and according to TTHome), you should be using the USA, Canada and Mexico v945.6245 which comes in at around 1875.11 MB as you say so you could try deleting most of the cspeech files from this to shrink it a bit & also you may need to trim your voices folder down too.

Alternatively you can use 945.6256 Android version which should be smaller as it has no cspeech files see [Only registered and activated users can see links. ]