I don't know much about diskspare.device, other than what I've just Googled. It sounds like it's just a slightly tighter packed format to squeeze even more data on each track?
As long as it's still double-density, written as a single bitstream, doesn't include any copy protection tricks, and the sector numbers are known, then it should be possible to support it. ADFRead assembles a complete track from fragments read in multiple passes, so I guess it should work much the same.
Might be safer to wait for Toni to confirm it though