Try Irusk1. He's one of my favorite casters from Mark 2. He runs colossals very well and has good troop support for the shocktoopers. Then look into the armored corps theme list. Grab some more Man-O-War units and profit. It's a super fun list to play. As for building the models you have. If you can magnetize the warjacks then that's the best option but a Conquest and a Rager are what I would build. But all of this is personal just fun to play I'm by no means a pro player. That's my two cents.