Instead of sorting by power, I almost always sort by ATK. My most powerful girls usually end up in team 1, which is NOT a bad thing, since that is the team that will help my allies. The more powerful the girls are in your first team, the less chance someone will drop you as an ally for a more powerful ally. Midgame, strong allies of variable speed are *extremely* important. People will pick specific allies for some maps because they're powerful enough and/or because their helper squad has a certain speed (like, a very powerful high speed squad to tank you through a map, or a squad with extremely low speed to take a specific short route to kill just one pest but not reach the boss before your regular units cleared all the other pests)

All my teams have one of each type, and then each team has a different type "extra". Most maps have a mix of 2-3 types of mobs, so each team has at least one knight who deals extra damage to whatever mobs they face.
Generally, my first two teams are a bit faster than the other two, and my last two teams is where I put "new girls" for a while until they're leveled high enough to replace a girl from one of the first two squads.