I've tried that too, but they don't recommend mixing higher than 50% matting agent and the 30% mix i tried was nowhere near flat enough. It looked more like acrylic does straight off the gun. Then I tried the matte clear and got a fantastic result. The other benefit of the clear is that you can use it over a metallic base for an awesome look and it's still a 2k finish. Late model R1 yamaha's use something like this effect in one of their colour schemes.
The matte clear is actually quite easy to work with. It didn't seem to matter if one area got a little more on it, the sheen level was very even. I'd be keen to try a bonnet in it.
fuck that's a nice colour, consider something like that when i'm sparying mine