Thinking about all of the replies has convinced me to drop the Tyrant+Tyrant idea. Instead i will go for the other suggestion of Lunar + Lunar.
That will give me 2 pairs each of Armageddon + Lunar (Big bro, little bro) plus Mars + Dictator..
Screened by Flachions, supported by Emperor/Apocalypse, with a couple of SM vessels for variety.
Thanks
James