Top end fishing charters

Am looking around at live aboard charters in the top end for sometime next year, somewhere between Derby and Darwin.

Has anyone ever been on any up there? any good or bad experiences?

Im assuming the best time of year is the same as karratha weather wise?, altho im guessing the tides and the wet season probably play a bigger part.

Looking at a 6-10 day charter if possible?

Cheers