Those problems can probably be solved with a larger board. (rolling fog has dissipate 3 so think about how long it takes the enemy to get within 0-1 zones of you, and most attack spells you can use the tower for only have 0-2 range).
Not sure if teams are allowed to have two of the same mage in the first place.
I would say if you're playing in team organized play, for the sake of better coordination and synergy between friendly spellbooks, it might be a good idea for one person to be the primary spellbook builder for both of their team's spellbooks. (Of course it's still vital to get feedback from your teammate about it.) Unless both teammates are really in sync with each other and on the same page AND approximately equally skilled in spellbook building. Then you might not need to designate a primary spellbook builder.