[tubbedII]

I read a lot negativity on 6x9's and that a 6.5" is better, but I plan to run 6x9's in the rear of my blazer anyway. I don't think you didn't anything "wrong" by using them in the kicks, but typically these are done with a good set of component speakers. Kicks are typically built to get a better sound staging since you can point/position the speakers towards the middle of the cab and head level rather than facing at your feet. I think the biggest issue with you using 6x9's there would be the amount of room they are taking up. Are they 2 or 3 way?

I wouldn't put anything above the seat back on the side. My dad's 69 had tweets in there and they were right next to your ear which actually hurt before you could turn it up nice and loud. Since you already have them built, I'd just toss a decent amp to the 6x9's and run them all by themselves to see how you like it and go from there.