Assymetric speaker cable lengths?

I'm setting up a system for a family member and the particulars of the room would require a 24 ft length of speaker cable to the right channel, but 10' would be enough for the left. This is a mid-fi tubed system.

Would it be OK to do this? I mean the signal travels at near the speed of light, so would it create a problem arriving at the left channel a nano-second (or less) sooner?

Many thanks