Last shop I was at just hooked up an airline to the tailstock. A valve to control the amount of air, and a Y-splitter to send air to each side.
Its been a while since I've been there but I do remember that the air went into the middle of each side of the tailstock base... I'm thinking they hooked an oiler up and got rid of greasing it.
It didn't take much air to lift it and I (150lbs of weak) could easily push it around.