you want evil? mixed company of mech and vehicle.
lance of 4 scouts, the faster and more mobile the better. spider is good for this, with its jump 8. with 2 spiders, one jumps in as the other jumps out, staying mobile without having to move too far away from the targets.
two lances of vehicles. each of these should be 3 LRM carriers and 1 SRM carrier.
spiders run up to scout, LRM carriers supply the indirect firepower from behind the hill. thats 18 LRM 20 per round, and if the enemy gets too close the SRM carrier will alpha strike them. however, you can only sustain that kind of firepower for 8 rounds- if anything survives that long, run away to reload.
you can do this with any kind of missile boats, but the LRM carriers are a special kind of deadly.