I say you upgrade the system to work just like the later 12-volt setup. You would have to study a wiring diagram for quite a while, but you should be able to make it work. You will have to modify the sockets to accept a dual filament bulb, but I think you will be happier overall. Used switches are not at all impossible to find especially in bad cosmetic shape. And if the old turn switches are similar in design with the newer ones, you can replace the arm and the plastic bit on the end with new stuff (so from the outside it will look new). I think IPD sells reproduction turn signal arm ends now.