I think it would be great if both clans had the option of saying they were ready for the war to begin. Once all prep has been completed both clans can elect to start the war at that time, rather than have to wait for the full 24 hours.
And if that was a good enough idea, allow clans to declare a war over. If it is completely out of reach let clans move onto the next war as long as both clans agree to end the war at that time.

