I think that 180mm will still have too much coverage.

I used a 100mm (approx.) projection Petzval on 4x5" and the "swirl" was outside the 6x7cm area you're after.

Don't forget that the closer you focus, the larger the image circle. This will push the swirl even further out.

Whats the FL on the new 35mm version that's on Kickstarter?