Thing is I have some cursed earth spawner rooms for Well of Suffering. And every now and then I come by some spawners, Dolly them and take them back home. So I thought I might as well stick them in the cursed earth rooms(it is not a matter of need, just a matter of "why not").I've always had the Spawner sit directly on a single block of Cursed Earth. I've not tested it hovering over one.
Is your plan to have a regular floor with one block of Cursed Earth, or a full floor of Cursed Earth? I feel like it might make a difference, but without more data...
Problem is that to get 100% value of the spawners, they need to be one block above the cursed earth. And it looks crap to have a free-standing block of cursed earth under the spawners. Hence my question if it was really necessary for it to be touching the spawner.