Thanks for reporting back.
You are not the first person that faces the problem of multiple configuration files 
Now you can turn on ipconfigUSE_TCP_WIN again?
Mind you, the following defines set the default sizes for your TCP stream buffers:
#define ipconfigTCP_RX_BUFFER_LENGTH ( 0x4000 )
#define ipconfigTCP_TX_BUFFER_LENGTH ( 0x4000 )
That is 16KB in both directions, which is good.
If you need a high-speed TCP connection, e.g. when streaming video, you can set the properties in a sock option called FREERTOS_SO_WIN_PROPERTIES.