Well I've decided to go with the defacto standard that a lot of sensors use. That is, the ordering GND, VCC, SIGNAL. The advantage of this is that if people use a bare header on my board they can plug in directly a defacto standard sensor. If people decide to use a keyed KK header instead (the silk screen will have the drawing of a keyed KK header) then they will have all the advantages of a connector that doesn't easily get knocked out. In this case, the pin out will be 1-GND, 2-VCC, 3-SIGNAL. This is not compatible with the Tinkerkit, but as I dig deeper it looks like the Tinkerkit gear, at least at this point in time, really isn't that popular and so not much to be gained from a pin out that would not be as flexible as the one I've decided upon.