I'm considering swapping the tuners on my Taylor GS Mini Koa for a set of Gotoh 510s. The actual process looks straightforward, including drilling pilots for the screws, I've no problem with any of it. However, imagine a line drawn through the guitar lengthwise, should a line through the centre of the tuner shaft and button intersect this at 90 degrees? Or is the final rotational siting of the tuner a matter of aesthetics and personal taste? Some instruments seem to have tuners at a slight angle.