Single layer is supported already since 5.0, only a question of supporting it with rewritable since 5.1
It works well for xbox1 games to be played on a X360.
Now the other reality is this
(v5.0) 360 file ISO support (Work in progress. New QWIX tool to come)
which means that the building of ISO image for the x360 game on SL is not ready.
Note that most game do not fit anyway, so some work is still required for cleaning/compressing/... in order to make them fit.
According to the release the QWIX team is working on it, and believe that Badsheepy is doing it as well.
look at the pinned for info on SL.