I have ignored this question from the beginning of my BIR cooking and just used what the recipes called for - "tomato paste". A huuuuge mistake to assume, 2x or 3x concentrated tomato paste from the can or tube would be alright. Even diluted with water it would easily tint every curry with a very strong aroma.
I had my eyes opened when I followed this recipe: 150 grams of double concentrate tomato paste, diluted with 300ml water, and added 1 teaspoon of tandoori masala powder, all mixed togehter and stored in the fridge. THIS is what I use now when a recipe calls for "tomato paste", and you can tell how much less of the concentrate now goes into a curry. I suggest you might try that and see the difference.