The original Bass VIs only had one truss rod. Remember that truss rods are not there to strengthen the neck, only to make the relief adjustable (read as: it will be fine with one). Make sure to post lots of pictures, I'll be watching this one with great interest as not a lot of people seem to make Bass VI styled instruments. Oh, also those tuners and bridges should be fine. If I remember correctly the strings have bass ball ends rather than guitar sized ones.
