can't help you with spacers. wheel ballast can be almost any liquid, depending on your climate. if you live where it gets below freezing, you need an additive which keeps your ballast from freezing. here in pa i use calcium chloride. it's heavy and works quite well. it is corrosive, so leaks need attended to asap to prevent rim rust (i'm ok with that, as leaks need fixed anyway). if you can find a local dealer, rim guard (beet juice) is non corrosive, but not as heavy. some people also use rv antifreeze.