ballast question

im doing a small sog setup and looking for a ballast that can do 600w and 1000w
just starting out slow and want to be able to upgrade the light from a 600w to a 1000w later
is there any ballast out there that can do that?

You *might* find a dual ballast that will do that.
But in general, its a matched set bulb/ballast.
They really aren't that expensive. Put the $$ into a great hood and ducting, then the ballast/bulb upgrade can be rather cheap. The hood /cordset should work with anything up to 1000W.