Locust would be the spotter for the Valkyries. Run as a reinforced company, a lance of lights, like the Locust, could hover at long range and call down the indirect fire quite safely.
TMM 3 + long range 4 + cover 1 + average pilot skill 4 = 12. That's pretty safe.
If the enemy charges in, then the Valks fight, while the Locusts try to get completely to the rear of the enemy. If the enemy has heavier long range units, like a company with 2 fire Lance's, assault class mechs like Awesomes or Longbows, then bag it.