I had a chance today to take a few test shots with my recently acquired Canon 135mm TS-E in combination with Canon extension tubes and the Canon 1.4x III TC. I used a portion of a ruler as a target, and attempted to keep the left edge of the frame lined up with the 100mm mark on the ruler. I've attached a few of the resulting images in the hope that they might help answer questions about 1:1 reproduction. The lens was set at its closest focusing distance and the camera was moved on a focus rail to achieve focus.
Mary