Some Tennis Tutor machine models have so called 2-line feature, with two settings: narrow and wide. What do they do? The dial on the control board seems to indicate I can set the machine to: - oscillation off - I'm assuming it means it will deliver the ball to one place - oscillation random - does it mean it shoots the ball to random places both in terms of court-wide and drop shot -deep ball? Or is it random left to right only? Is there any way to adjust/tell it how random it is? - 2line narrow - does it mean it shoots the ball basically to fh and bh (of one player) - 2line wide - does it mean it shoots the ball basically to the left and right of the court so two players can practice? the models that have single oscillation setting - is it basically 'random oscillation' as described above? Also - is it possible to add 2 line functionality to a machine that has 'oscillation on/off' only (essentially I'm asking if the circuitry/mechanism is there and the dial is just not included but could be relatively easily wired.