As a perfectionist, I always try to wave in every fight.
Sometimes it's an inconvenience when deciding the number of each kind of troop to send while looking at the predicted battlefield and the ongoing combats (normally tens of batches if someone doesn't withdraw the survived troops/ships from previous rounds), and there is very limited time to think.
So, to avoid unwanted mistakes, I suggest adding buttons to customize several troop formations and deploy them when sending attacks.
Those may look like:
Also adding some ratios (1/2, 1/3, 1/4, etc.) in the troop selection can help:
or
.
