Seeking Advice: RAK4631 Solar Node Setup for Low-Light/Cloudy Conditions (Galicia, Spain) - With Part List

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I'm working on deploying a fixed Meshtastic repeater node in Galicia, Spain. Our region is known for heavy cloud cover and low solar irradiance a good portion of the year, especially during winter.

My primary goal is continuous 24/7 operation with maximum power autonomy. I'm focusing on low-cost components from Aliexpress since I plan to build several nodes.

I am purposefully choosing a DIY approach using separate, components, as I don't fully trust the long-term reliability of all-in-one pre-built solar kits from Aliexpress (like the one linked below in the comment section, for example). Mostly because I don´t find much information online, are this any good?

PART LIST IS IN COMMENTS:

My theoretical reserve is 10–12 days without sun. Given the lack of solar during Galician winters, is a 4000mAh LiPo generally accepted as enough reserve, or should I try to find a larger battery (e.g., 6000mAh) that fits?

I chose a 10W panel to ensure that the RAK's built-in charger (which limits current to around 350-500mA) is fed enough power even on heavily overcast days. Is this a solid strategy for maximizing charging on cloudy days, or is a smaller, more efficient low-light panel (if such a thing exists affordably on Ali) a better choice?

I also don't know much yet about Antenna Mounting and how to keep Humidity out,