Jerry, perhaps it might be better to consider more traditional dishes from scratch, rather than trying to create a healthy BIR curry. The wife came home last week with a Low Fat Fat Free recipe book . It had in it a recipe for Fragrant Chicken Curry. Of course this caught my eye so we tried it last night.
The recipe was described "In this dish, the mildly spiced sauce is thickened using lentils rather than the traditional onions fried in ghee".
I spotted an error in weights and measures of the recipe which made me nervous, but nonetheless we tried it and it was very easy to make. Simply added .5 cup of lentils to a pan with 2 tbls of mild curry powder, 1 tsp or corriander, 1 tsp cumin seeds and 2 cups veg stock. Simmered for 10 mins added 8 skinless chicken thighs and 8oz shredded spinach and simmered for 40 mins.
I was quite surprised with the dish, it wasn't bad at all. I will replace the veg stock with chicken stock next time round and may add some fenugreek. But overall, we had clean plates all round. Different, but quite nice and definitely out of the box. The best part was that the on its own a single portion was only 152 Kcals, I served it with coconut rice and giant crisps.

On the balance of spicing, could you make a larger quantity of masala and then just take from that overall like you would a spice mix?
Dry fried onions or roasted in the oven I have tried and without oil, they always taste boiled with charred edges. I think the key to fry onion without oil is to do it on a low heat. The problem is when the sugars start to caramelise the onions will stick to the pan.