To rainscreen or not to rainscreen?

Hello GBAers,

I'm building a small (250 sq. ft.) cottage in my backyard in the Bay Area in California in climate zone 3C. We plan on using stucco for the exterior as it will match the main house.

The cottage will have one-foot overhangs because it's near the property line. Code around here is two layers of Grade D building paper under the stucco, but I know a lot of you guys believe it's better to add a rainscreen between the paper and the stucco.

In my research, it seems that a lot of the rain screen products are insanely expensive.

Considering my location, do you think I could safely use maybe two layers of 15# roofing felt without concern for moisture destruction?

If you still think that's an unwise move, do you have advice, or even better, instructions for how to add furring strips beneath the stucco? I know that you can get paper-backed wire but I worry that the walls will end up super wavy since the wire won't have as much support behind it.

Thanks.