Analysis Plus Oval Copper 9s or 12s

I currently am using the Analysis Plus Oval 12 cable in my system and I am considering upgrading to the Oval 9s. Has anyone compared the performance of these two cables against each other? For those of you who have auditioned both at home, is it worth the extra cash for the 9s?

I am also thinking about biwiring with the Oval 12 instead of getting the Oval 9s. By the way I am using the Magnepan 1.6qrs.
I got Oval 9's with jumpers from Audio Advisor instead of bi-wiring.The Jumpers were $75, a lot less than another run of 9's. They are made from 12's. I really liked the results.I needed 10 ft. runs of speaker wire, so it was a good option.
I would expect a vast improvement in bass. Definitely try it out, on loan if you can. I bought them on trial from Audio Advisor and ended up keeping them. They are not so expensive that getting them used (vs new) is critical.