I too am struggling to dial in my brush busting layers for western WA!!.... Unfortunately I haven't found exactly what I'm looking for....
Best I've come up with for different temps:
Dry conditions- screw it and destroy my Sitka core lightweight base, destroy my pro merino 200 mid, strong fleece 210 (often too warm), or axis hybrid (too warm unless absolutely frigid out)
Wet conditions- strong fleece 210 (not water proof but less sweat than rain jackets or warmer yet options), kuiu axis hybrid jacket, sitka thunderhead (eventually wet brush pushing on the material will wet through), or kuiu Yukon on a full heavy rain.
My issue is I sweat so bad in almost anything it doesn't matter if it's waterproof... The only exception is if it's crazy cold out and I'm severely under dressed, but even then the second I walk 100 yards with any pack on, my back is already sweaty and wet. Last year in Idaho hunting in 2F-16F morning conditions I only had a pro merino 200 on while moving...
So alas my struggle is- more than anything I want a durable shell for brush that adds little to no warmth, breathes, pit zips, and has a full front zip... I actually don't care if it's waterproof at this point cause I'm either going to get wet from sweat, brush, or if it's storming and I wear my Yukon gear then we circle back round to the sweat wet. There's no staying dry for me- it's not possible, so at this point I'm looking to just be less hot and more comfortable while wet.
I want something like a strong fleece but next to zero fleece brushing on the inside and full zip. I could always layer up or down under it instead of the protective shell adding to the layering.
I just want a protective shell for brush with pit zips and a full front zip that's it, nothing more.