My first heavy is a rifleman. Usually, these mechs have great weapons loadout, but horrible anything else. That's why I've swapped out one of the large lasers for a medium laser, to mount extra ammo, cooling, and armor to protect those beefy weapons. This is looking to be a great upgrade to my blackjack!
Keep an eye out for a Legend Killer. It will be able to run this load with almost 10 extra tons for extras because of the XL engine.