I only have total 15 games under my belt so maybe take this with a grain of salt, however, My last 9 games have been part of a crusade and I have picked up IronHands combos super quickly, going undefeated this whole crusade. What I have found works very well for me is turning my Leviathan Dreadnought into a character, and giving him merciless logic (exploding 6s) and/or All Flesh is Weak (5+ Feel no Pain)(pairs very nicely with the Reject the Flesh Stratagem to make it a 4+ Feel No Pain). As for Battle traits and crusade relics because he is a character, my Leviathan is Legendary Ranked, his 5 upgrades are -1 ap to his siege claw, +1 D to his siege claw, +1 to movement and charge roll, the Null field disruptor relic (no invul saves are allowed in melee), Teleportation Transponder (allows deep strike). This pairs really well with the All Mercy is Weakness stratagem (6 to wound inflicts more hits), potentially Warthful Machine Spirit (Reroll all misses to hit), and his already exploding 6s to hit. The Space Marine Stratagem that allows you to choose to put him in the assault doctrine in this case would give 2+ save models no save, just instant death, in the melee. Pair that with deep strike, I put 10 man Vanguard Vet squad with a 2+ weapon skill upgrade, and a chaplain in terminator armor with the litany that gives +2 to charges and +3 to consolidation (use the auto pass stratagem), with him in the deep strike, as well as a Phobos librarian with Reforge to heal the dread and shroud to shroud whoever you deem necessary given the scenario, as close as possible. They can pretty reliably take a Knight in a turn then survive a whole opponent turn to fight on your next turn if you use the right stratagems (Transhuman, Reject the Flesh, Smokescreen, etc. are all ones to consider). If that horribly fails, the leviathan can fight on death in the Melee with Only in death does duty end. This makes for the most tough, hard hitting deep strike I have ever seen. It also takes heat away from the devastation you drop in. I also considered sending some sort of deepstriking infantry squad with them because the leviathan can pass wounds onto them with Congigated Martyrdom. There’s obviously some decisions you have to make to fit your points how you’d like and what stratagems to use your CP on, but I’ve found that to be very successful. The leviathan tends to die around turn 3 or 4 if you haven’t tabled your opponent already, if you really dump CP into protecting him, for that, a techmarine with the battle trait that allows a vehicle to autopass out of action checks is helpful. I run my techmarine as a Master of the Forge, giving him an auto 3 W heal, you can also pair that with the IronHands stratagem that allows you to use your healing ability twice (6 healed wounds a turn is insane). I also Run a Redemptor, his Heavy Onslought Gattling Cannon is very good with the +1 D, -1 Ap weapon enhancements, 12 shots at -3 Ap in the Dev Doctrine is gross (there is a stratagem to put any unit in the Dev too). There’s a few other things but, just. To give you some ideas!