Dragonheart, yes, you need to thin it with acetone. I pour some into the top of my dip tube, the kind with the big reservoir on top, and work it in with an old arrow shaft. Takes a while to mix it. It should be about the consistency of honey. Too thin and it will keep wiping off, and too thick and the finish will crack. If you get it too thin, just leave the top off for a while.
Mine has been in the same tube for a decade or more, and I just add more GL or more acetone as needed.