Are we using the Power Armour options/History from Rites of Battle? I ask because there are some noticeable differences in terms of available power armour during the Great Crusade/Ullanor Campaign. Mark 7 and 8 don't exist yet, Mark 6 is a relatively recent innovation, Mark 5 doesn't exist either yet (it is called Heresy Armour for a reason afterall).
So In practice we've got access to Mark 2, Mark 3, Mark 4, and Mark 6 Armour. Maybe something like this for the dice bracket?
1-3: "Crusade" Armour
4-6: "Iron" Armour
5-9: "Maximus" Armour
10: "Corvus" Armour