im for one stack 2 just looks like crap and 6 in is about the max i think looks good on an idi
im going to run one 5 inch stack flat black with a flapper
What you're doing looks fine. We have farm trucks all over teh place here that have utilitarian stacks and they look nice, they don't look all stupid like the little pickups with the 6" pipes sticking out of the beds.
For farmers a ground exhaust is often referred to as a brush burner. They;ve been running cobbled stacks up alongside their flatbeds for years, they just haven't been chrome for the most part so nobody pays much attention