I don't think that's 370mm rotors on that 370Z. Hat style looks like it's a 345/355mm rotor setup.
Here's a pic of my setup with my 20" reverse lip with Rotora 8pot/15"rotor. I have just a tad more than 0.5" Clearance between the caliper and the wheel. When I shopped for Work wheels with step lips, Work USA Confirmed to me that their 20" step lip (of the Schwert SC1) will not clear the diameter as it's a bit smaller than their regular 19" Reverse lip
I'm not sure if SSR's barrel design is the same.
Nevertheless, I'm super anxious to see that your setup will work. And it's a great feeling to know that your vendor/sponsor is backing you up.