You'll need to drill holes. And your challenge is to make the holes equal on each side. You could do four or six on each turret. You'll need to make sure that each plate is the same distance from the front of the car, and equal distance from the centre of the car, then make sure that the holes are aligned so that each plate is at the correct angle.
Imagine your plate is a clock. Both plates 12.00 marker should point forwards. Then you'll need a hole at 2.00, 4.00, 6.00, 8.00 and 10.00. This is difficult to get right.
I made a measuring device like a clock with hands fixed two hours apart. Drill one hole at 12.00 and the other hand will point to 2.00 so you know where to drill.
It's a royal pain in the arse. A horrible fiddly job.
Charlie