Germany's options against British 18-inch-gun capacity

What could Germany do if it knew Britain could build 18-inch guns rather than only 15.7-inch weapons?

Very little could erase Britain's industrial advantage; Germany would still face a navy able to build more ships and heavier armament at scale.

Knowing Britain could build 18-inch guns would not solve Germany's underlying quantitative problem. German engineers could still produce strong individual weapons and ships. Britain's ability to outbuild Germany in yards, heavy weapons, and supporting infrastructure mattered more than gun caliber alone. Industrial depth could make a technically impressive German reply strategically inadequate.