Well you don't pick 20 40mm bases and expect to hit with all of them.
20 Seqs = 9 Greatmaces = what you want to hit with
Give these guys the reroll hit, reroll wound, reroll save.
Why 20?
15->20 = free (40pts :x) 11 Seqs acting as "health buffer" before you start losing your Greatmaces
... now if you still don't like them, you got 10 evoc for the same price