Yes, that's around 1:9 although it's not critical to be totally precise. I tested several strengths and germination within four weeks in peroxide:water started to become less at around 1:13. The weaker the solution the less beneficial the peroxide soak. Soaking in plain water actually slowed them down compared to not soaking at all, so at some point between 1:15 and plain water the solution presumably becomes weak enough to start being inhibitory rather than helping but I didn't test at what point that was.
Looking at my notes it took around two to three weeks for about half of the test seeds to germinate, and most had germinated by four weeks in the peroxide solution, until it got down to somewhere between 1:13 and 1:15 peroxide to water, which is where germination started to lessen.
