Quite roberjerman. Most people say that you should use equal lengths for both channels everywhere. This is expensive and leaves a lot of curled up wire around. As long as the wires are specified to operate well at the longest lengths and overall kept as short as possible you will be fine. You want to run the largest gauge you can afford. Check out Kimber Kable. If you are handy with a soldering Iron Kimber will sell you rolls of their best wire (8 gauge) and you can terminate them yourself saving lots of money.
The next time you look at amplifiers you might want to consider balanced monoblocks as placing them behind the speakers and running long signal cables an very short speaker wires is an advantage.
The next time you look at amplifiers you might want to consider balanced monoblocks as placing them behind the speakers and running long signal cables an very short speaker wires is an advantage.