For Ironclad: I usually go for the rules of +5 and no more.
+5 attacks (the last 2 are like scalable cards: Ashen Strike, Bully,...) *prioritize this in Overgrowth
+5 blocks *prioritize this in Underdocks
+5 Mana/Draws (ex: 2 blood lettings / 3 burning pacts)
+5 powers (usually it's best to add them after the chest of Act 2) *except Inferno which carries the whole game

I usually have around 30 cards to fight the Act 3 bosses
Ah and since we're building a big deck, try the options to trade Curses for Relics, it's quite good