Drubin makes a good point, and I agree with Kijanki's assessment as well. If you haven't already done so, maybe try hooking up one leg of the Oval 9s (being careful not to let any of the unused terminals touch each other of course), which may give you some insight into how the VSs react to biwiring vs. single wire hookups apples to apples. Also, how long did you have the Oval 9s in your system -- maybe they need some more time to break in or settle into your system?
FWIW, I have both Satori shotguns and single wire and prefer the shotguns by a fair margin. Increased clarity and dynamics are the main benefits, but whether that's due to my speakers working better biwired, decreased capacitance of the higher overall gauge of wire, etc. I don't know. Probably worth a look if you're up for it. By the way, what kind of improvements were you looking for and what characteristics of the Oval 9s had you convinced they would be that much better? Just curious (I've never heard the Oval 9s myself).