Maddox needs twice the usual red lyrium to modify my armor properly; taking over as the Vessel means it has to be perfect. Have the amount ready in three days, and you and your squad will get a chance to serve as Corypheus's honor guard.
My own proving goes on. When I first donned the armor, I thought I was drowning in fire. Without Corypheus to stop me, I'd have torn my own skin off. Now the armor's settled, I can march for days without rest, break a man like kindling. I'm finally fit to be the Vessel.
Maddox may come to you to work on my armor's modifications. If he gives you instructions about the lyrium, follow them to the letter. Treat Maddox like you'd treat me.