Water proofing Stucco Dome

This is my first Post. My 42 oven is complete up to the perlite insulation layer and final flue duct installation.

After I install final duct, I plan on adding stucco. I am trying to figure out best approach to making the stucco water resistant best I can. I saw from Gulf recommending Drylok and/or acrylic fortifier. Wanted to see if there were other suggestions out there.

A summary of my build is as follows:
1) Oven has been cured. Cured with lamps, small fires and have since had a few large fires and taken oven up to 1000 deg F. No cracks yet.
2) I need to finalize my duct on my chimney, what is shown in my pic is smaller than what I will eventually install, 8" duct.
3) I live in San Diego, CA. We don't get a lot of rain here. 1st priority will be to put stucco, then long term put a roof over the oven. For now, tarps have worked during the early part of the year when it rained.
4) I have a breather vent at the top of the dome
5) My build has these details: Floor: 4" perlite+Board+bricks. Dome: 2 layers of blanket+6-8 in perlite insulation layer.

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