All the way, with housings leaving the bar tape and going to the "wrong" shifter boss (i.e., left front barcon goes to the right shifter boss, then wires crossing under the downtube to reach their proper derailleurs). That gives the largest diameter bends and the smoothest shifting. I was always afraid that the routing that exits the bartape would result in my becoming hopelessly tangled and likely dying in a horrible crash as a result. (I'm klutzy.)