Building a GW Tau Fleet?

[mdauben01]

I thought I was done starting new BFG fleets, but I just stumbled over a good deal on colleciton of NIB GW Tau ships and couldn't resist.  Since I've never played with or against the BFG Tau, thought I'd ask for a bit of guidance.  Right now I have (or soon will) the following:

1 x Explorer Class Battleship
1 x Merchant Class Cruiser
1 x Hero Class Cruiser
3 x Defencer Class Escorts
3 x Orca Class Escorts

By my count, this is around 725 pts worth of ships.  What should I try and track down to build this up to 1000 pts?  How about 1500 pts?  More cruisers?  More escorts?  Another Battleship?  I see the three Tau "capital" ships are each available in two variations.  Are either of them clearly better or worse for any of the big ships?  Are the Nicassar Dhows, Kroot Warsphere or Demiurg Bastion worth adding to the basic Tau fleet (assuming I can find and afford them)? 

Any suggestions or tips on the Tau fleet are more than welcome!   

[fracas]

More heroes and a second explorer

[horizon]

Although what Fracas says is true it will create a Tau fleet like most have. But, it are the best options to start with.

Adding a Demiurg Stronghold is certainly cool idea. Good ship as well.

[Aldaris]

And fun too! Blast marker vacuum cleaner. Demiurg - the deadliest janitors in Spaaaace!