Probably the easiest way to gain power quickly in a tourney would be to go CoC Mage.
That is also an easy way to gain power quickly in CB1: start FB mage, switch to CoC when you have enough exp.
However, you often need more than 1 minion to survive ranged, and this is even truer here, where CoC does not fire until melee.
Anyhow, nobody uses tanks (unless obliged by the rules, or it is an arena tourney), since mages are much more effective against high PR chars (I mean nobody that wants to win the tourney).
However, as MM pointed out, it is up to the imagination of the organizer(s) to make so that "non-standard" chars remain competitive.
One of the best ones (IMO) for instance was the
T150 - In honor of private, where all kind of strats appeared.