Custom exhaust ideas

In '99, I bought the TTI set-up; headers AND full length 3" duals, for my 68 Barracuda with set-up similar to yours; 367/4gear/stock tank.
The kit at that time had pipes too long,so as to fit either 108, or 111 cars, so some trimming was required.I worked from the back o the front. It came with the H-pipe, and fit like a glove; with the pipes coming out between the springs and the tank.
Later I moved the springs with the 3\4 inch kit, and still later I added the GVOD, and it still all fit EXCEPT the H-pipe. I had to cut it out.
I immediately noticed the missing H, and spent a lotta time that summer trying to find the missing bottom-end torque. I ended up with a 3.09low box and 3.55s,which took care of it. I don't miss the H anymore. And with just a 230* cam,(maybe a tic over 400hp) I don't feel the need for an X.
I ordered their pipes with turndowns, that I just barely poked out the valence and ended under the bumper. I smoothed the rearmost edge so it can't cut skin. Great sounding, and no drone with the also supplied Dynomax 3-pass crimped-seams muffs. No rust-out still today
_________________________________
But I can sure see a problem with springs moved in 3 inches; my pipes just barely fit between there. I can definitely see the pipes having to be outboard of the springs.
So your idea of dumping out the side behind the wheels makes sense, altho, with stuff sticking up thru the hood, Ima thinking your power level is a might bit higher than mine, and so probably; it's gonna be LOUD,lol