Duro Fork Question

I purchased some Duro carbon forks from Zinn, which relocate the caliper (flat mount) so that it requires a minimum 180mm rotor size. Next I purchased an adapter from Paul’s that (a) converts from flat mount to post mount caliper, and (b) moves caliper from 160mm to 180mm.

I have asked both Zinn and Paul’s and nobody can tell me what final rotor size I will need. I am guessing 200mm, but I really don’t know.

To simplify my question… hypothetically: if you stack two identical 160mm-to-180mm adapters, will this require a 200mm rotor?

From the information here, you end up with a 200mm rotor.

You got the +20mm adapter, correct?

Yes, 200mm. Make sure the fork is rated for a 200mm rotor (which I assume it would be, if Zinn is selling it). Is it for a Clydesdale/tandem?

In case it’s helpful to anyone, the same goes for native FM160 forks like the Open U-turn when you fit a +20mm caliper like the Hope RX4.

Yes, I got the +20 adapter… thanks!

I asked Zinn if it was rated for 200mm and they said hell yeah. They even sell an adapter just for the Duro forks which is for 203mm rotors.