When is unequal, equal?

Space accordingly but keep the cable lengths identical.

So your speakers are about 8 feet apart, right?
Well you're right about all the extra speaker cable, to say nothing of the extra money if it's decent cable. (Because if one of them would be over 10 feet, it would be good to have them the same length.)

Personally, a better way to do it, both in terms of economics AND sonics, would be to place the amps between the speakers using a longer pair of ICs from preamp to amp (I guess about 10 feet based on your information?) and then a pair of 6 foot +/_ speaker cables. Or you could place an amp next to each speaker (but using two ICs the same length) and use really short speaker cables, maybe 3 footers. That would be the best IMO.

If you can used balanced XLR ICs to connect the preamp with the amp, that is desireable, but not essential.

Since the signal approaches the speed of light in your spkr. cables, unequal lengths are of no concern in your system.

Porziob is correct about the speed of light, etc. however speaker cable length over 10 feet tends to diminish the damping factor -- the amp's ability to accurately control the woofer, necessary for clean bass.

This is even more important if one is using a tube amp, since output transformers have inherently limited damping capability. That is why (unless they are just driving the high frequencies) you so often see tube amps sitting right next to speakers.

thanks to all for the suggestions...All of the above options mentioned have already been explored. The only way the system can be laid out requires the question I have posed. "WAF" won't allow for the placement of amps out in the room, next too the speakers (my solution). Hence the need for the long runs of cable. As for the cost considerations I agree, however I already own them so my true cost is to have one of the runs shortened. If the speed of sound/light is correct? then I see no sonic benefits to the equal lengths...Correct?