Better with castors that can be locked methinks. But TBH I also would find it hard to slide around on it under the Disco even if I could get it into the garage, my gut precluding.....Make some wooden wedges should work ??
So I put down a piece of hardboard from the back of an old kitchen cupboard which has a shiny side I can slide on, or a piece of shiny faced ch!pboard.
I don't slide well on 1" gravel!!