The person that sets the rally onto the ruins should be the person with the highest hall of war. It’s good to try and organise various times of that day where the people with the biggest hall will set consistently. Whatever times work for your alliance.
The hall of war article explains how you can increase the hall with alliance technology.
Always run ruins twice every day
The requirements for completion of the next wave of ruins will be as follows
When joining ruins the people that send army should be the people with the highest tier of troops.
Sending 1 troop is good enough when the run is nearing capacity, it’s important to get as many people as possible through each run.
The number of troops you personally enter does not effect the outcome for rewards. The rewards are randomly sent to all participants of the rally. 1 troop can get better rewards than full army.