Hmmm, I would say start with B7V9.
First burn @8x. If not good (PIE max >280, PIF max > 16) try another one to check if you have a bad media. If good then burn @16x. If not good, try again @16x. If the second one is good, stick with B7V9.
Obviously, if the second 8x not good, go down to B7U9 and B7T9. That's how I would test if I got a new drive.
chas0039 suggestion is also fine although I would suggest starting from B7T9.