Speaker cable length for L/R channels critical?


I have a good system that utilizes some older discontinued speaker cable that I like a lot. It is 10 feet in length and I need that length to reach the left speaker. The amp is not (and cannot be) located center between the speakers.
The problem is I wish to biwire and have an opportunity to buy a 6 foot pair. The question is this: Can I run both 10 foot cables to the left speaker and run the 6 foot pair to right without any wierd effects like "ghosting" or have one channel be clearer or louder than the other? Any ideas? Thanx
ceb222
Also:
2 tweeters that roll off at the example freq or 22khz and 33khz will also have a phase shift difference even well below their roll off freq, in the audioable range. Much of music is composed of impluses which are composed of the fundamental freq and some harmonics of that freq. If the phase relation of these harmonics are affected by the tweeter roll of freq, then you change its sound.
does this explain why, when I turn on my sub, the entire frequency range that the main speakers produce, top to bottom, sounds richer to me? I've wondered about this recently.
Thanks,
Art
OK, so here is a question.

What is better? To have a 4 foot and 10 foot run? or to have two 10 foot runs where the excess cable will end up spooled on the floor?
I would definitely have the 2 10-foot runs.
At one time I had a similar unequal run of Cardas Cross to my Aerial 10ts & it always sounded funny & flat & I always had to move my chair around. I switched to equal lenghts of Cardas Golden Ref (still have them--great, smooth cable, even in extra-long lengths) & everything clicked into place. I would never have an asymetric set of any cables--just bad karma.