I highly rate the Taz base, but agree that its not easily translated to the sweeter stuff - CTM, Korma... If Mick has any of Taz' methods on these that would be hugely appreciated.
But the point I wanted to discuss more was the notion of "reduction". Almost every chef video we've seen the chef starts with (depending on the curry) garlic, ginger, tom puree, spice mix and chilli. Then they add watery base gravy, and the vast majority of the of the cooking time is spent reducing this down. This must be a critical part of the BIR taste. If they all aimed for efficiency, they would make thicker base and have quicker curry cook time.
Perhaps part of this reduction theory is why I rate my curries using this base so highly, as the method forces you to do a complete reduction.
Some have commented negatively against the Taz method, as it doesn't follow the usual "fry spices and pastes in oil". However it does provide a focus on the reduction part.
Just an observation I thought I'd share.
-- Josh