I dont want to be a prude but as a LONG TIME car audio guy can I make a serious auditory suggestion????
Save your self some time with the amp wiring. I assume that you have a 4 channel amp also from the description you gave?
Bridge the amp to 2 channels and power your front components with it. I'd even consider getting rid of the 6x9's all together to be honest with you (from experience) BUT if you still want to run them, just throw deck power at them and then proceed to dial your stereo in with the fader set all the way to the front and then stop the minute you start to hear absolutely any sound out of them.
Think of it this in a number of ways:
1. How good would a concert be if you sat with your BACK facing the stage
2. How many home stereos have the front speakers and center channel BEHIND you??
3. At most you should use rear speakers to bring rear seat passengers a little sound (obviously not an issue in your car) or to move the sound stage slightly rear ward if required.
4. Speakers should be round (LOL) non-round speakers sound like... NON-ROUND speakers!!!
5. Try the set-up with no rears at all, if you don't like it, then try out the rears but deck power only. With equal power to each, you'll over power the fronts really wasy. You'll get way nicer sound with the fronts getting all your amped power.
I just wanted to offer a little advice due to the fact that you've obviously done a lot of work on this car and you obviously have a lot of pride in your work and want the best result.
T