You could try the "holzhaufen" or "holzhausen" stacking method, which is a circular woodpile design that doesn't require a roof. It’s sturdy, allows for good airflow, and helps the wood dry out more evenly. You stack the logs in a circular pattern, leaning them inward as you go up, and top it with a cone-shaped pile to help shed rain. It’s a space-efficient option that doesn’t need a tarp or roof.

If that doesn’t work, a simple crisscross pattern stack (also known as a "log cabin" style) can provide better airflow than a basic pile, and throwing a tarp over that will help keep it dry.

Good luck with the extra firewood!