you can not reduce the size of a transaction now. it is too late for that. you already have a ton of "transaction outputs" which you have to spend each of them. and when you do that, each of them add extra bytes to your final transaction size.
what people have been explaining so far is a workaround to "split" the already big result into multiple chunks so that you can broadcast it since very big transactions are rejected by the network as nonstandard. so go back and read what they've suggested and do them!