3 guides
The four joiner slots are decided by join order — offensive rallies only by pre-assignment, garrisons by promotion cycling. Plus why 20% skills lose, Mia's 43.75% EV, and the filled-in Gen 12 table.
Stop memorising joiner tables and compute them: three leaders and a troop ratio in, slot saturation, widget firing, dead class-locked skills and ranked joiners out. 45 heroes built in.
Stop memorising joiner tables and derive them: SkillMod split into nine slots, the +100% vs +144% stack-vs-split gap proved, plus the investment threshold that decides who actually gets picked.