I think the way you have arranged the knobs is as good as you could have done given that there are eight! But if you ever get worried about having eight knobs there maybe you could try using different sizes to help explain their functions?
I've that on some of my filter preamp builds, as I find it helps a lot onstage. In this case the round ones are standard Vol/Vol/Bass/Mids and the two pick shaped ones are the filter section, resonance and frequency: