Please think about adding two things on Grand Arena:
1. Allow to change defense squads before deadline. Currently single misclick can ruin entire thing.
2. Allow to form both Offence and Defense squads in defense deployment phase. Yes, in theory it can be done in common in-game squads interface, but as I understand there is no way to filter out units which used in other squads here - not very convenient when you need to form many squads without intersections.