I know this is an old post, but i'm hoping to help someone else with what i learned this weekend.
Catapult version C2:
2 LB-2x and 2 LRM 15s with a 0,1,or 2 gunnery skill.
I park it behind cover, or the rest of my unit, and with the low Gunnery, it's able to donate SERIOUS LRM fire support to the battle. AND, when the VTOLs come in, the LB-2s with a -7 (-3 Cluster and -4 for 0/4 skill) that knocks them down every time.
In the past, I've had a problem with donating valuable BV just to shoot down low BV VTOL targets. THIS unit allows me build a unit that can really contribute offensively to my own battlefield agenda (2LRM15s) and contribute defensively to incoming VTOL (2LB-2xs).
In addition, if we play double blind on megamek, then I can BLIND the other team while keeping my VTOLs in the air for gathering movement information.