This was one of the reasons for considering the Heavy Weapon Platforms. I would hope to weaken a point in the enemy lines and then concentrate all the Wraithguard on that point. Because the units are quite small, but also quite deadly, it makes sense to concentrate them where they can be most effective.
Tactically I would need to disembark the units in the place that they can do maximum damage, and where the enemy response would be limited. The Wave Serpents can then usually attack from behind the enemy's lines, and provide a screen to prevent the majority of the enemy army returning effective fire.
Careful management of resources required, me thinks.
All that is important is known.