The target-substrate distance might make some difference, but I don't
think it's a big driver here.  I don't think I explained my theory very
well in my last post.

The percentage of oxygen in your film should be dependent on the
relative percentage of oxygen in the IO target.  For example, if you're
using a 50/50 In/O target, you will get XX% of oxygen in the resulting
film.  On the other hand, if you're using a 70/30 I/O target, you will
get something