They seem to be a little hard to find at times too. Now the unmodified bulkheads can be had for few bucks per pair. Brass tubing runs under a buck and that will create enough bushings for quite a few cars.
Lets do a very cost effective thing here and create and install our own bushings.
Most pin vices come with multiple chucks and one will usually fit this drill bit. Usually come in 1 foot lengths. I bought a few just to have on hand. Should spin like a top if the fit is right. Then check for play.