k9copy is great and is a nice addition to Ubuntu.

I'm using the DVD Copy feature from ISO to ISO, which works fine.
However, it keeps shrinking the ISO (7GB) to 4.7 GB.

k9copy determines its shrink factor to reach that 4.7GB value, and I don't see a way to change that (the problem is that the 4.7GB is a bit bigger than what can accept my (blank) DVD-Rs.

There is a per-title factor, but ideally a global shrink factor (or , better, a target size) would be great. Is there a way to do set the shrink size/target size?