I've been using CA's mix powder along with his base for some time with good results but I've recently broken with that and have been experimenting with my own concoctions just to see what influence what is having on the final flavour.
I've just recently made a batch my own base sauce which wasn't significantly different to anything else you'll find here but I wanted to experiment with cooking technique and ingredient ratios, specifically the onion weight to other vegetable (green pepper, carrot, cabbage, tomato) weight and to water + oil volume ratio to solid (onion + vegetable) ratio.
I also created my own mix powder to go with it because I wanted to remove the standard pre-bought ground Madras powder component to see what effect it was having. It was basically 4 parts Turmeric, 3 parts coriander, 2 parts cumin, 1 part paprika, 1 part chilli powder, 1 part fenugreek powder, 1 part garlic powder, 1/2 part ginger powder, 1/2 part cardamon powder, 1/2 part garam masala, 1/2 part mustard powder and 1/2 tsp fennel seeds, 1/2 tsp black peppercorns and 1 star anise all ground.
So far it's not been hugely different to what I've been used to but I've only made once dish with this so far so it's early days.